Enhancements to location-based services functionality in a radio telecommunication network

[0001] This non-provisional patent application claims priority based upon the prior U.S provisional patent application entitled “ENHANCEMENTS TO LOCATION-BASED SERVICES FUNCTIONALITY IN A RADIO TELECOMMUNICATION NETWORK”, application Ser. No. 60/262,092, filed Jan. 16, 2001, in the names of Susan Anctil, Jose Arturo Arreaga Garza and Lan Tran.

[0002] 1. Field of the Invention

[0003] The present invention relates to a system and method for retrieving the geographic position of a mobile station in a radio telecommunication network.

[0004] 2. Description of the Prior Art

[0005] Nowadays, the mobility of a mobile subscriber is an important issue in a radio telecommunication network. It is essential that services for which a mobile station (MS) user has subscribed in his home network follow him whenever he roams in a network or hands off to another network. The mobility issue is well known in the art and described in a plurality of standards such as in the American National Standards Institute (ANSI). The ANSI-41 protocol defines the MS geographic position retrieval for a roaming subscriber. This allows providing a MS geographic position to service applications (SA) such as law enforcement, emergency services (e.g. 9-1-1 calls) and location-based services.

[0006] However, before providing the MS geographic position to service applications, an implementation of a MS location functionality has to be done in the radio telecommunication network. In a radio telecommunication network that follows the ANSI-41 protocol, a mobile switching center (MSC) provides and sends geographic location data of the MS to a mobile positioning center (MPC). A position determining entity (PDE) then calculates the geographic position of the MS by using geographic location data sent by the MSC. The MPC stores that geographic position and renders it available to authorized network entities.

[0007] Today, with the introduction of several service applications and various systems, it can be difficult for network operators to provide a high level of security. Consequently a mobile subscriber's privacy is questionable. It is described in a plurality of standards that a mobile subscriber is allowed to restrict the access to his geographic position. More particularly, in the ANSI-41 protocol a subscriber can activate/deactivate the presentation of his position. As an example, Location Information Restriction (LIR) restricts presentation of a MS position information in a radio telecommunication network.

[0008] There are two different aspects regarding the control of a mobile subscriber on his location information privacy. In a first aspect, the MS geographic position can be retrieved with the approbation of the MS user. A MS user can authorize a network operator or a service provider for retrieving his geographic position upon subscribing to available and offered services (e.g. location-based services) in his home network. In a secondary aspect, the MS geographic position can be retrieved without the approbation of the MS user (law enforcement or emergency services (e.g. 9-1-1 calls)). As known today, a plurality of governments from different countries have adopted laws regarding the implementation of these service applications in radio telecommunication networks.

[0009] Then, in a way to restrict the access to a mobile subscriber's location, it is necessary to make sure that the MS geographic position is requested by an approved network entity. It is essential for a network operator to certify that the network entity is therefore one that is authorized to ask for the MS geographic position. Consequently, there is a need to improve the security aspect related to geographic positioning of mobile stations and the providing of such information to service applications. The present invention provides a solution to this effect.

[0010] It is therefore one broad object of this invention to provide a high level of security for a geographic position of a Mobile Station (MS) by rendering the MS geographic position available only to authorized network entities or Service Applications.

[0011] More particularly, the present invention provides a system and method for retrieving the geographic position of the MS. The system and method comprise a home Positioning Node (PN) for receiving a MS Geoposition Request from a Service Application (SA), and for generating a Positioning Request message including a home Positioning Node identification parameter. The system and method further comprise a serving PN for receiving the Positioning Request, and for validating the home Positioning Node identification parameter prior to sending the geographic position of the MS to the SA. The home PN comprises an Input/Output Unit for receiving a MS Geoposition Request from the SA, for sending an Authorization Request message for requesting an authorization for the MS Geoposition Request to a Global Database (GD), for receiving an Authorization Response from the GD, for sending a Positioning Request message including the home Positioning Node identification parameter to a serving PN, and for receiving a Positioning Response from the serving PN. If a hand off has occurred, the system and method also comprises an anchor Switching Node (SN). The anchor SN comprises an Input/Output Unit for receiving the Positioning Request from the home PN via an anchor PN, for forwarding the Position Request to a serving PN via a serving SN, and for sending a Positioning Response to the anchor PN.

[0019] The following abbreviations are being used throughout the present application:

[0020] GD: Global Database

[0021] HLR: Home Local Register

[0022] ISPOSREQ: Intersystem Positioning Request

[0023] ISPOSREQFWD: Intersystem Positioning Request Forward

[0024] LCS: Location Services

[0025] LD: Location Detector

[0026] MPC: Mobile Positioning Center

[0027] MS: Mobile Station

[0028] MSC: Mobile Switching Center

[0029] PDE: Position Determining Entity

[0030] PN: Positioning Node

[0031] POSREQ: Positioning Request

[0032] RTN: Radio Telecommunication Network

[0033] SA: Service Application

[0034] SN: Switching Node

[0035] Reference is now made to FIG. 1 there is shown a message flow diagram illustrating the flow of messages in the present invention for retrieving the geographic position of a Mobile Station (MS) (not shown) in a Radio Telecommunication Network (RTN) 100. The RTN 100 comprises a Home network 104, an Anchor network 108 and a Serving network 112. As well, each network (Home network 104, Anchor network 108 and Serving network 112) comprises different entities, which realize the steps of the invention. The Home network 104 comprises a Positioning Node (PN) 116 and a Global Database (GD) 120. The Anchor network 108 comprises a PN 124 and a Switching Node (SN) 128 while the Serving network 112 comprises a PN 132, a Location Detector (LD) 136 and a SN 140. The MS is registered in the Home network 104. If the MS is located in the Home network 104, the Home network 104 is called the serving network of the MS. However, the MS can roam in different networks. A network where the MS roams becomes the serving network of the MS. However, if the MS hands off to another network the original serving network will be called the anchor network and the new network where the MS is located becomes the serving network.

[0036] The flow of messages starts when a Service Application (SA) 144 requests the geographic position of an MS. The SA 144 sends to the home PN 116 an MS Geoposition Request 148 for requesting the geographic position of the MS. The home PN 116 obtains data from the MS Geoposition Request 148 and authenticates the SA 144. After that authentication, the PN 116 sends an Authorization Request 152 including a home Positioning Node identification parameter (home PNID 154) to the GD 120 for authorizing the MS Geoposition Request 148 and for obtaining data. The GD 120 authorizes the request and sends an Authorization Response 156 to the home PN 116. The Authorization Response 156 comprises a serving SN identification parameter and an associated serving PN network address. Subsequently, the PN 116 sends a Positioning Request 160 including the home Positioning Node identification parameter (home PNID 154) and the serving SN identification parameter to the identified PN 124. The PN 124 uses the home Positioning Node identification parameter (home PNID 154) to determine if the Positioning Request 160 has been originated from an authorized network entity. Following this determination, the PN 124 uses the received serving SN identification parameter for sending a Positioning Request 164 to the SN 128. The SN 128 is capable of determining if the MS has handed off to another network. If the MS has handed off to another network, the SN 128 forwards data obtained in the Positioning Request 164 in a Forwarded Positioning Request 168 to the new serving SN 140. Next, the serving SN 140 sends a Positioning Request 172 including the home Positioning Node identification parameter (home PNID 154) to the serving PN 132. The serving PN 132 uses the home Positioning Node identification parameter (home PNID 154) to determine if the Positioning Request 160 has been originated from an authorized network entity (home Positioning Node 116). Following this determination, the serving PN 132 uses data obtained in the Positioning Request 172 for selecting an appropriate LD (LD 136), which determines and sends the geographic position of the MS to the PN 132. More particularly, the selected LD 136 determines the geographic position of the MS by communicating with the SN 140 and the PN 132, “(PN 132-SN 140-LD 136) Signaling” 174. Next, the serving PN 132 replies to the Positioning Request 172 with a Positioning Response 176 including the geographic position of the MS (geopos 178). The SN 140 is then able to answer to the Forwarded Positioning Request 168 received from the anchor SN 128 with a Forwarded Positioning Response 180 including the geographic position of the MS (geopos 178). The SN 128 then answers the Positioning Request 164 from the PN 124 with a Positioning Response 184 including the geographic position of the MS (geopos 178). Following that message, the PN 124 returns the geographic position of the MS (geopos 178) to the PN 116 in a Positioning Response 188. Afterwards, the PN 116 sends a MS Geoposition Response 192 including the geographic position of the MS (geopos 178) to the requesting SA 144.

[0037] The invention can be applied to a plurality of telecommunication network protocols known in the art. As an example we refer now to FIG. 2. In FIG. 2 there is shown a message flow diagram similar to FIG. 1, but now applied to the signaling in an ANSI-41 network. The ANSI-41 network 200 comprises a Home network 204, an Anchor network 208 and a Serving network 212. As well, each network (Home network 204, Anchor network 208 and Serving network 212) comprises different entities, which realize the steps of the invention. The Home network 204 comprises a Mobile Positioning Center (MPC) 216 and a Home Location Register (HLR) 220. The Anchor network 208 comprises a MPC 224 and a Mobile Switching Center (MSC) 228 while the Serving network 212 comprises a MPC 232, a Position Determining Entity (PDE) 236 and a MSC 240. The MS (not shown) is registered in the Home network 204. If the MS is located in the Home network 204, the Home network 204 is called the serving network of the MS. However, the MS can roam in different networks. A network where the MS roams becomes the serving network of the MS. However, if the MS hands off to another network the original serving network will be called the anchor network and the new network where the MS is located becomes the serving network.

[0038] The flow of messages depicted in FIG. 2 starts when a Location Services Client (LCS Client) 244 requests the geographic position of an MS. The LCS Client 244 sends to the MPC 216 an Intersystem Positioning Request (ISPOSREQ) 248 for retrieving the geographic position of the MS. The ISPOSREQ 248 includes a Position Quality of Service parameter (PQoS) for specifying the required quality of service for the MS position, a LCS Client identification parameter (LCSCID) for identifying the LCS Client 244 and authentication data parameter (Authentication_Data) for authenticating the LCS Client 244 in the MPC 216. With the parameters and data included in the ISPOSREQ 248, the MPC 216 authenticates the LCS Client 244 and verifies that the LCS Client 244 is authorized to request the MS geographic position. Next, the MPC 216 sends to the HLR 220 a Positioning Request (POSREQ) 252 message including the LCSCID and a home MPC identification parameter (MPCID) for authorizing the ISPOSREQ 248, and for obtaining data. More particularly, the HLR 220 validates the identity of the LCS Client 244 using the received LCSCID and a list of valid LCS Clients, authorizes the ISPOSREQ 248, and sends a posreq 256 to the home MPC 216 for authorizing the ISPOSREQ 248. The posreq 256 comprises an MS identification parameter (MSID) for identifying the MS, a network address (MPCADRR) of the MPC 224 associated with the MSC 228 where the MS last registered and a MSC identification parameter (MSCID) for identifying the MSC (MSC 228). Subsequently, the MPC 216 sends an ISPOSREQ 260 to the identified MPC 224. The ISPOSREQ 260 comprises the received PQoS, MSID, MSCID, LCSCID and home MPC identification parameter (MPCID(home)). The MPC 224 uses the MPCID(home) to verify that the ISPOSREQ 260 has been originated from an authorized entity (MPC 216). Following this determination, the MPC 224 sends an ISPOSREQ 264 to the MSC 228 by using the received MSCID. The MSC 228 is capable of determining if the MS has handed off to another network. If the MS has handed off to another network, the MSC 228 forwards the required parameters obtained in the ISPOREQ 264 (MSID, LCSCID, PQOS, and MPCID(home)) in an Intersystem Positioning Request Forward (ISPOSREQFWD) 268 to the new serving MSC 240. The serving MSC 240 sends to the associated MPC 232 an ISPOSREQ 272 including the MS information (MOBINFO) needed to determine the MS geographic position, the MS positioning capabilities (MPCAP parameter), the MSID, the received PQoS and the MPCID(home). The MPC 232 uses the MPCID(home) parameter to verify that the request for the MS geographic position has been originated from an authorized entity (MPC 216). Following this determination, the serving MPC 232 uses the PQoS and the MPCAP parameter for selecting an appropriate PDE (PDE 236), which determines and sends the geographic position of the MS to the MPC 232. More particularly, the selected PDE 236 determines the geographic position of the MS by communicating with the MSC 240 and the MPC 232, “(MPC 232-MSC 240-PDE 236) Signaling” 274. Subsequently, the MPC 232 replies to the ISPOSREQ 272 with an isposreq 276 including the geographic position of the MS (POSINFO parameter). Upon receiving this information, the MSC 240 answers the ISPOSREQFWD 268 by sending an isposreqfwd 280 including the received POSINFO parameter to the MSC 228. The MSC 228 returns the POSINFO parameter to the MPC 224 by sending an isposreq 284. The MPC 224 returns the POSINFO parameter to the MPC 216 in an isposreq 288. Afterwards, the MPC 216 generates and sends an isposreq 292 including the geographic position of the MS (POSINFO parameter) to the requesting LCS Client 244.

[0039] Reference is now made to FIG. 3, which is a block diagram illustrating the PN 116, FIG. 4, which is a flow chart that demonstrates the steps for positioning the MS in the RTN 100 and further to FIG. 1. The PN 116 comprises an Input/Output Unit 300 for receiving messages from other network entities and Service Applications, and sending generated messages, a Processor 310 for processing messages, a Message Generator 320 for generating outgoing messages, an Acknowledge functionality (ACK) 330 for accessing an internal database, and a Position Database 340 for storing the geographic position of mobile stations. At step 400, the PN 116 receives the MS Geoposition Request 148 from the SA 144 at the Input/Output Unit 300. At step 410, the Processor 310 verifies that the SA 144 is authorized to request the MS geographic position. If the SA 144 is authorized, the PN 116 will generate and send the Authorization Request 152 to the GD 120 at step 420. If not, the PN 116 will deny the MS Geoposition Request 148, generate and send a message to the requesting SA 144 at step 430. The following steps are executed in the case that the SA 144 is an authorized SA. At step 440, the PN 116 receives an Authorization Response 156 from the GD 120. Subsequently, the PN 116 generates the Positioning Request 160 to the PN 124, at step 450. At step 460, the PN 124 uses the home Positioning Node identification parameter (home PNID 154) included in the Positioning Request 160 to determine if the Positioning Request 160 has been originated from an authorized network entity. If the network entity (PN 116) is not authorized, the PN 124 will generate a message for denying the request (step 430). If the request has been originated from an authorized entity, the PN 124 generates the Positioning Request 164 to its associated SN 128 (step 470) and receives the Positioning Response 184 from the SN 128 (step 480) prior to sending the Positioning Response 188 to the home PN 116, at step 485. The Processor 310 processes the Positioning Response 188 received from the PN 124 and, by using the ACK 330, stores the geographic position data of the MS (geopos 178) obtained from the Positioning Response 188 in the Position Database 340. Next, the geographic position data of the MS is returned to the requesting SA 144 at step 490. More particularly, the Processor 310 processes the request from the SA 144 and the ACK 330 allows accessing the geographic position of the MS stored in the Position Database 340.

[0040] Reference is now made to FIG. 5, which is a block diagram illustrating the SN 128, FIG. 6, which is a flow chart that demonstrates the steps for retrieving the geographic position of the MS in the RTN 100, and further to FIG. 1. The SN 128 comprises an Input/Output Unit 500 for receiving messages from other network entities and for sending generated messages, a Processor 510 for processing messages, a Presence Determiner 520 for determining that a MS has handed off to another network and a Message Generator 530 for generating outgoing messages. At step 600, the SN 128 receives the Positioning Request 164 from the PN 124. At step 610, the Presence Determiner determines that the MS has handed off to another network. Following this determination, the SN 128 forwards data obtained from the Positioning Request 164 to the new serving SN 140 in the Forwarded Positioning Request 168, at step 620. Next, the SN 140 sends the Positioning Request 172 to the new serving PN 132 (step 630). At step 635, the PN 132 uses the home Positioning Node identification parameter (home PNID 154) to verify if the Positioning Request 172 has been originated from an authorized network entity (PN 116). If the Positioning Request 172 is not from an authorized network entity, the PN 132 will deny the Positioning Request 172 (step 640). The following steps are executed in the case that the PN 116 is an authorized entity. At step 650, the PN 132 selects an appropriate LD (LD 136) based on the data obtained from the Positioning Request 172. In return, at step 660 the LD communicates with the serving SN 140 and the serving PN 132 for determining and sending the geographic position of the MS (geopos 178) to the PN 132. At step 665, the PN 132 sends the geographic position of the MS (geopos 178) in the Positioning Response 176 to the SN 140. Following this message, the SN 140 sends the obtained geographic position of the MS (geopos 178) in the Forwarded Positioning Response 180 to the anchor SN 128, at step 670. Afterwards, at step 680, the anchor SN 128 processes and generates the Positioning Response 184 including the geographic position of the MS (geopos 178) to the requesting PN 124.

[0041] Although several preferred embodiments of the method and system of the present invention have been illustrated in the accompanying Drawings and described in the foregoing Detailed Description, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications and substitutions without departing from the spirit of the invention as set forth and defined by the following claims.