Method and system for managing mobile station location information

Mobile stations initiate location determination sessions, such as at predetermined time intervals, with a wireless telecommunications network. The wireless telecommunications network obtains the locations of the mobile stations as a result of the location determination sessions, and the mobile station locations are stored in one or more location registers. The location information stored in the location register(s) may then be used by location-based applications. For example, an application may request that the wireless telecommunications network provide a specified service to the mobile stations that are located in a specified zone according to the mobile station locations stored in the location register(s).

BACKGROUND

1. Field of the Invention

The present invention relates to telecommunications and, more particularly, to methods and systems for managing mobile station location information.

2. Description of Related Art

Wireless telecommunications networks are increasingly using wireless location technologies to determine the locations of the mobile stations they serve. As a result, there is an increasing interest in developing location-based applications, i.e., applications that make use of mobile station location information. These location-based applications may simply track or monitor the locations of mobile stations, or they may provide information or services to mobile stations based on their locations. Such location-based applications may be internal to the wireless telecommunications network, or they may be third-party applications that obtain the locations of mobile stations from a location server or other entity in the wireless telecommunications network. For example, the Location Inter-operability Forum (LIF) has developed the “Mobile Location Protocol Specification” (version 3.0.0 published on Jun. 6, 2002) to define an access method that allows applications to query a wireless network for location information.

One difficulty with expanding the use of location-based applications is that the process of obtaining mobile station locations for the applications may consume substantial network resources. In particular, wireless telecommunications networks typically initiate location determinations in order to respond to requests for location information from location-based applications. Thus, as the number of location-based applications requesting location information increases, and the number of mobile stations being located increases, the load on the wireless telecommunications network may correspondingly increase substantially.

Accordingly, there is a need to obtain and provide mobile station location information more efficiently.

SUMMARY

In a first principal aspect, an exemplary embodiment of the present invention provides a method of managing location information relating to a mobile station. The mobile station is able to send receive communications via a wireless telecommunications network. In accordance with the method, the mobile station initiates a location determination session with the wireless telecommunications network. The wireless telecommunications network obtains a location of the mobile station as a result of the location determination session, and the location is stored in a location register of the wireless telecommunications network.

In a second principal aspect, an exemplary embodiment of the present invention provides a method of managing location information relating to a plurality of mobile stations. The mobile stations initiate location determination sessions at predetermined time intervals. The locations of the mobile stations are obtained as a result of the location determination sessions, and the locations are stored in at least one location register.

In a third principal aspect, an exemplary embodiment of the present invention provides a system for managing mobile stations location information. The system comprises a location gateway, a position determining entity (PDE) communicatively coupled to the location gateway, and at least one location register. The location gateway receives requests from mobile stations to initiate location determination sessions. In response, the location gateway determines whether permissions to locate the mobile stations have been obtained. The PDE obtains the locations of the mobile stations during the location determination sessions, and the at least one location register stores the locations.

In a fourth principal aspect, an exemplary embodiment of the present invention provides a method of providing location-based services in a wireless telecommunications network serving a plurality of mobile stations that have mobile station locations stored in at least one location register. In accordance with the method, a request that a specified service be provided to mobile stations located in a specified zone is received. Zone-located mobile stations are identified by determining which of the plurality of mobile stations are located in the specified zone, according to the mobile station locations stored in the at least one register. The specified service is provided to at least one of the zone-located mobile stations.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The present invention, in its preferred embodiments, provides a wireless telecommunications network with location information in advance of specific requests from location-based applications. In particular, the mobile stations themselves initiate location determination sessions with the wireless telecommunications network, as a result of which the wireless telecommunications network obtains the locations of the mobile stations. Preferably, the mobile stations initiate the location determination sessions at predetermined time intervals, such as every 15 minutes. However, the mobile stations may also be able to initiate location determination sessions at other times, i.e., “spontaneously.”

The locations obtained in this way are stored in one or more location registers in the wireless telecommunications network. Internal and third-party location-based applications may then use the location information stored in the location registers. In many cases, this stored location information is sufficient for the location-based applications, such as being recent enough, so that the network will not need to make additional location determinations to respond to requests from location-bases applications. In this way, network resources may be conserved.

Referring to the drawings,FIG. 1is a simplified block diagram of an exemplary wireless telecommunications network10in which exemplary embodiments of the present invention may be employed. Wireless telecommunications network10includes a base transceiver station (BTS)12that provides a wireless coverage area within which BTS12may communicate with one or more mobile stations, such as mobile station14, over an air interface. Mobile station14may be a wireless telephone, a wirelessly-equipped personal digital assistant (PDA), or other wireless communication device. The communications between BTS12and mobile station14may occur in a digital format, such as CDMA, TDMA, GSM, or 802.11x, or they may occur in an analog format, such as AMPS. A preferred wireless communications format is “CDMA 2000,” such as described in EIA/TIA/IS-2000 Series, Rev. A (published March 2000), which is incorporated herein by reference.

BTS12is controlled by a base station controller (BSC)16, which, in turn, is controlled by a mobile switching center (MSC)18. MSC18is connected to the public switched telephone network (PSTN)20and may use an out-of-band signaling system, such as Signaling System 7 (SS7) to route calls through PSTN20. MSC18is also able to signal to a home location register (HLR)22and to a service control point (SCP)24. This signaling may occur via one or more signal transfer points (STPs), such as STP26. The signaling between MSC18and HLR22may conform to IS-41 specifications. A recent revision of the IS-41 specifications, ANSI/TIA/EIA-41-D-97, published in December 1997, is incorporated herein by reference. The signaling between MSC18and SCP24may conform to the specification “Wireless Intelligent Network,” TIA/EIA/IS-771, published in July 1999, which is incorporated herein by reference. Other signaling protocols could be used, however. In this way, MSC18, BSC16, and BTS12may connect incoming calls from PSTN20, which calls may originate from calling parties using landline telephones, mobile stations, or other communication devices, to mobile station14. Similarly, MSC18, BSC16, and BTS12may connect calls originating from mobile station14to their destinations, via PSTN20.

Mobile station14is also able to access a packet-switched network30. Packet-switched network30may include one or more local area networks (LANs) and/or one or more wide area network (WANs), such as the Internet. Packet-switched network30may route packets using a network protocol, such as the Transmission Control Protocol/Internet Protocol (TCP/IP).

To provide access to packet-switched network30, BSC16may include a packet control function (PCF), and a packet data serving node (PDSN)32may connect BSC/PCF16to packet-switched network30. The communications between BSC/PCF16, MSC18, and PDSN32may conform to “third generation” (3G) specifications. Examples of such 3G specifications include “Wireless IP Network Standard,” 3GPP2 P.S0001-A, dated Jul. 16, 2001 and “3GPP2 Access Network Interfaces Interoperability Specification,” 3GPP2 A.S0001-A, dated June 2001, which are incorporated herein by reference. Briefly stated, under these 3G specifications, when mobile station14requests packet data service, BSC/PCF16may engage in signaling with MSC18and with PDSN32to authenticate and authorize mobile station14and to set up a data link with PDSN32. If this process is successful, a point-to-point protocol (PPP) session is established between mobile station14and PDSN32. PDSN32then acts as a network access server, providing mobile station14access to packet-switched network30. In some cases, mobile station14may use the Wireless Application Protocol (WAP) for communications via packet-switched network30, in which case the communications may occur through a WAP gateway34.

Packet-switched network30may also carry communications related to the process of obtaining and providing location information relating to mobile stations, such as mobile station14. In this regard, wireless telecommunications network10may include a position determination entity (PDE)40. As described in more detail below, PDE40may be able to communicate with mobile stations, such as mobile station14, in location determination sessions carried over packet-switched network30, during which PDE40may determine the locations of the mobile stations. In some embodiments, PDF40may not be able to communicate using the TCP/IP packet format used in packet-switched network30. Accordingly, PDE40may be communicatively coupled to packet-switched network30via an interface application42that converts between the communication formats used by PDE40and packet-switched network30.

As described in more detail below, the mobile station locations obtained in location determination sessions may be stored in one or more of location register(s)44, which may be communicatively coupled to packet-switched network30. In an exemplary embodiment, location register(s)44comprise a plurality of regional location registers. In particular, each regional location register may be associated with a geographic region, such as a region of the United States, and stores the locations of mobile stations that are located in its associated geographic region.

Wireless telecommunications network10may also include a location gateway46, communicatively coupled to packet-switched network30. Location gateway46may manage the processes of obtaining and utilizing mobile station location information in various ways. For example, location gateway46may be involved in setting up location determination sessions between mobile stations, such as mobile station14, and PDE40. For example, network10may be configured so that it does not locate a particular mobile station or provide location-based services to the mobile station unless the mobile station “opts in” by granting permission to be located and/or to receive specific location-based services. Accordingly, network10may include a permissions database48that stores information regarding the permissions that network10has obtained. Preferably, permissions database48is external to locations gateway46, or wholly or partially internal to location gateway46, so as to be accessible to location gateway46. Before setting up a location determination session between a mobile station, such as mobile station14, and PDE40, location gateway46may query permissions database48in order to check whether network10has obtained permission to locate the mobile station.

Location gateway46may also serve as a gateway for applications seeking access to the location information contained in location register(s)44. Such location-based applications may include internal applications50and/or third-party applications52. Internal applications50may be treated by wireless telecommunications network10as “trusted” applications and may access location gateway46, such as via packet-switched network30, without network10applying security measures. In contrast, wireless telecommunications network10may require third-party applications52to access location gateway46via a wireless application manager54, which, in turn, is communicatively coupled to location gateway46via packet-switched network30. As described in more detail below, wireless application manager54may use a security service to authenticate and authorize third-party applications52before allowing them access to location gateway46.

In addition to the foregoing, many other network elements may be communicatively coupled to packet-switched network30and may be able to communicate with mobile station14via packet-switched network30.

Exemplary operations are described below with reference to the exemplary architecture ofFIG. 1, with mobile station14as a representative of a plurality of mobile stations served by wireless telecommunications network10. One exemplary operation relates to the process of obtaining the location of mobile stations, such as mobile station14, and storing the location in location register(s)44. As described in more detail below, the location of mobile station14may be obtained as a result of a location determination session. Another exemplary operation relates to the utilization of the location information stored in location register(s)44, such as by internal applications50and/or third-party applications52.

a. Location Determination Sessions

In an exemplary embodiment, the process of obtaining the location of mobile station14begins when mobile station14initiates a location determination session with wireless telecommunications network10. Mobile station14may initiate the location determination session autonomously. For example, mobile station14may be programmed to initiate a location determination session at predetermined time intervals, such as every 15 minutes.

Mobile station14may also initiate location determination sessions spontaneously. For example, an application running on mobile station14may cause it to initiate a location determination session at times other than the predetermined time intervals. Similarly, a network element in wireless telecommunications network10, such as location gateway46, may send a send a signal to mobile station14to cause it to initiate a location determination session at times other than the predetermined time intervals.

Wireless telecommunications network10obtains the location of mobile station14as a result of the location determination session initiated by mobile station14. The specific manner in which the network10obtains the location will, in general, depend on the type of location-determining technique that is used and the specifics of the information that is exchanged during the location determination session. The communications between mobile station14and wireless telecommunications network10in the location determination session may conform to the specification “Position Determination Service Standard for Dual-Mode Spread Spectrum Systems,” TIA/EIA/IS-801, dated Oct. 15, 1999, which is incorporated herein by reference. Other protocols may be used, however.

In a preferred embodiment, wireless assisted GPS is used to determine the location of mobile station14. In the wireless assisted GPS approach, mobile station14includes a Global Positioning System (GPS) receiver but does not determine its location on its own. Instead, a location server in network10, such as PDE40, determines the location of mobile station14, typically in terms of latitude and longitude, based at least in part on information provided by mobile station14. For example, mobile station14may first send its approximation location, such as the cell or sector it is operating in, to PDE40. Using this approximate location, PDE40determines what GPS satellites are in view and their Doppler offsets and then sends this information to mobile station14as “assistance data.” Mobile station14then uses this assistance data to acquire GPS signals from the GPS satellites and, thereby, obtains information, such as pseudoranges, from which its location may be calculated. Mobile station14sends the pseudoranges and/or other location-related information to PDE40. PDE40then calculates the location of mobile station14, such as in terms of latitude and longitude, based on the information from mobile station14and, optionally, various corrections. In this way, wireless telecommunications network10obtains the location of mobile station14as a result of the location determination session.

However, other techniques for determining the location of mobile station14may be used. For example, mobile station14may use its GPS receiver to determine its location without network assistance. In that case, mobile station14may simply send to PDE40or other network element its calculated location, e.g., its latitude and longitude, during the location determination session. Alternatively, location technologies that do not rely on GPS may be used to determine the location of mobile station14.

In a preferred approach, wireless assisted GPS is used, as described above. In addition, mobile station14preferably communicates with PDE40via packet-switched network30, so as to avoid additional loading of the circuit-switched side of wireless telecommunications network10. Thus, mobile station14may communicate with PDE40using IS-801 messages that are encapsulated in TCP/IP packets.

Mobile station14may initiate a location determination session by first initiating a TCP/IP session via PDSN32. Mobile station14may then begin the location determination process by sending PDE40an IS-801 message encapsulated in TCP/IP packets. For example, mobile station14may include a Qualcomm gpsOne-enabled chipset that generates the IS-801 message. The encapsulated IS-801 message may traverse PDSN32, WAP gateway34, and packet-switched network30and may be reviewed by location gateway46before reaching the PDE40.

Location gateway46unwraps the IS-801 message and queries permissions database48to determine whether the sender has given permission to be located in this manner. If the sender has not given permission, location gateway46may return an “ask” message to mobile station14that asks whether the user will give permission to being located. The user may respond to the “ask” message, and mobile station14may transmit the response to location gateway46. In addition, subscribers may be able to use their mobile stations to turn their permissions on and off as desired at other times.

If the appropriate permission is indicated, either in permissions database48or in an affirmative response to the “ask” message, location gateway46encapsulates the IS-801 message into TCP/IP packets and sends it to PDE40. If PDE40is unable to use the packet format used by packet-switched network30, then interface application42may unwrap the IS-801 message from the TCP/IP packets and deliver the IS-801 message to PDE40. Alternatively, location gateway46may be able to send the IS-801 message to PDE40directly.

After PDE40receives the initial IS-801 message, PDE40and mobile station14may continue to communicate as needed in order to complete the location determination. As noted above, the messaging required for PDE40to obtain the location of mobile station14will, in general, depend on the type of location technology that is used.

Once PDE40obtains the location of mobile station14, the location, the mobile identification number (MIN) or other identifier of mobile station14, and a timestamp are stored in location register(s)44. In a preferred approach, PDE40sends the location to mobile station14, and mobile station14sends its location, such as in an XML message, to the one of location register(s)44associated with its geographic region. Alternatively, PDE40may send the location to location register(s)44without going through mobile station14.

FIG. 2is a simplified call flow diagram for the exemplary process described above. As indicated by step100, mobile station14initiates a location determination session by transmitting a session initiation message that is received by location gateway46. As noted above, the session initiation message of step100is preferably carried over packet-switched network30, such as in the form of an IS-801 message encapsulated in TCP/IP packets, and it may traverse various network elements, such as PDSN32and WAP gateway34, before reaching location gateway46.

In response to the message of step100, location gateway46may check the permissions stored in permissions database48to determine whether a permission to locate mobile station14has been obtained. For example, location gateway46may send permissions database48a query that identifies mobile station14, such as by MIN, as indicated by step102. Permissions database48may return a response that includes the permissions, if any, associated with that MIN, as indicated by step104. If the response of step104indicates an appropriate permission, then location gateway46forwards the session initiation message to PDE40, as indicated by step106. As noted above, the session initiation message of step106may reach PDE40via packet-switched network30and interface application42.

PDE40and mobile station14may then continue to exchange messages so that PDE40obtains the location of mobile station14. In the wireless assisted GPS approach, PDE40may send assistance data to mobile station14, as indicated by step108. Using this assistance data, mobile station14acquires location information from GPS satellites, such as pseudoranges, and sends the information to PDE40, as indicated by step110. PDE40then calculates the location of mobile station14, such as in latitude and longitude, and sends the calculated location to mobile station14, as indicated by step112. Mobile station14, in turn, sends location register(s)44a message that includes the calculated location of step112, MIN or other identifier of mobile station14, and a timestamp, as indicated by step114. More particularly, mobile station14may send the message of step114to the one of location register(s)44associated with the geographic region in which mobile station is presently located, which location register then stores the relevant information contained in the message, e.g., the location, MIN, and timestamp.

b. Utilization of Location Information

One of the benefits of having the mobile stations initiate location determination sessions is that the mobile station locations are already stored in location register(s)44in advance of specific requests by location-based applications, such as internal applications50and third-party applications52. Thus, when a location-based application needs mobile station locations, the application may, in many cases, use the information already stored in location register(s)44, rather than requesting network10to use its resources to find mobile stations. More particularly, internal applications50may query location gateway46, and third-party applications52may query location gateway46via wireless application manager54, to make use of the location information stored in location register(s)44. In this way, the location information stored in location register(s)44may be used to support broadcasting and multicasting technologies.

For example, the present invention may provide an application programming interface (API) that location-based applications can use to target multiple mobile stations located within a specified zone. Specifically, network10may support a Loc(Zone) API that location-based applications may use to request that a specified service be provided to multiple mobile stations located in a specified zone, based on the locations stored in location register(s)44. The “zone” may be defined in a number of different ways, such as by zip code, postal code, city, or latitude and longitude ranges. In many cases, the specified service may involve delivery of a message to the mobile stations located in the zone. The message may, for example, include text or graphics that a mobile station may be able to display or to save for later use. As other examples, the message may instruct the mobile station to generate a sound, vibrate, provide some other user-discernable indication, or perform some other function. In other cases, the specified service may relate to the process of setting up broadcast or multicast calls or to some other type of service.

When an application uses the Loc(Zone) API, location gateway46queries location register(s)44for an identification of the mobile stations, such as by MIN, that are located in the specified zone. If multiple regional location registers are used, then location gateway46may direct its query to the one or more regional location registers associated with geographic regions overlapping the specified zone. Location register(s)44may send location gateway46a response that indicates the MINs of the mobile stations currently located in the specified zone, based on the mobile station locations stored therein.

Location gateway46receives the MINs from location register(s)44and determines which of the identified mobile stations have granted permission for the service specified by the location-based application. For example, location gateway46may provide the MINs to permissions database48, which may respond with the permissions associated with the MINs. In this way, location gateway46may determine which mobile stations in the specified zone have authorized receipt of the specified service. Location gateway46may then provide the specified service to the authorized mobile stations. For example, location gateway46may deliver a message to the authorized mobile stations using SMS, WAP push, e-mail, instant messaging, or other delivery method.

After the mobile stations receive the message or other service, the mobile stations may send acknowledgements back to location gateway46. Location gateway46may then notify the requesting application when service delivery is complete. Location gateway46may also provide the requesting application with other service-related information, such as the number of mobile stations who received the message or service.

FIG. 3is a simplified call flow diagram for the exemplary process described above, for the case where the requesting application is one of third-party applications52. As indicated by step200, third-party application52sends a Loc(Zone) request to wireless application manager54. The Loc(Zone) request of step200specifies a zone and a service to provided to mobile stations located in the specified zone. For example, the Loc(Zone) request may specify a message, such as an alert or a coupon, to be delivered to the mobile stations in the specified zone. In response to the Loc(Zone) request, wireless application manager54may authenticate and authorize third-party application52for the specified service. Wireless application manager54then forwards the Loc(Zone) request to location gateway46, as indicated by step202.

In response, location gateway46sends location register(s)44a query that includes the specified zone, as indicated by step204. As indicated by step206, location register(s)44responds with an identification, such as the MINs, of all of the mobile stations that are located in the specified zone, according to the mobile station locations stored in location register(s)44. As indicated by step208, location gateway46may then send permissions database48a query that includes the MINs or other mobile station identifications obtained in step206. Permissions database48responds with the permissions associated with the MINs, as indicated by step210.

From the permissions obtained in step210, location gateway46determines which of the mobile stations identified in step206have authorized the specified service. Location gateway46may then provide the specified service to the authorized mobile stations. For example, location gateway46may send messages to the authorized mobile stations, such as mobile station14, as indicated by step212. The mobile stations, such as mobile station14, may send back to location gateway46acknowledgements that they have received the messages, as indicated in step214.

Location gateway46may then send a service complete message to wireless application manager54, as indicated by step216. The service complete message may include the number of messages sent to mobile stations located in the specified zone and/or other information relating to the specified service. However, depending on the location-based application, the service complete message may or may not identify specific mobile stations, such as by MIN, that received the message or other service. Wireless application manager54then forwards the service complete message to third-party application52, as indicated by step218.

Preferably, the Loc(Zone) API uses the mobile station locations determined in advance and stored in location register(s)44, such as in the manner shown inFIG. 2and described above. However, the Loc(Zone) API may also be used when the locations of multiple mobile stations in the specified zone are determined in other ways.