Procedure and arrangement for providing location information on a communication terminal device

Abstract

Procedure for providing a reliable location for a communications terminal, comprising the following steps: - Obtaining an initial location for the terminal device via an initial access mechanism, - Obtaining a second location for the terminal device via a second access mechanism, where the first and second access mechanisms are used in different access networks; characterized by - Comparing the first and second locations obtained, and - Validating the location of the terminal as reliable if the first and second locations obtained are found to be substantially the same, where the validated location of the terminal device is used to consider at least one of the first access mechanism or the second access mechanism as reliable for further location determinations without validation from another access mechanism.

Description

TECHNICAL AREA

[0001] The present invention generally relates to a method and device for certifying the location of a communication terminal device. In particular, the invention can be used to ensure correct location information during calls from parties, when required for emergency calls or when needed for various location-based services. STATE OF THE ART

[0002] With the advent of 3G mobile telephony, new packet-based communication technologies have been developed for transmitting multimedia content. For example, technologies such as GPRS (General Packet Radio Service) and WCDMA (Wideband Code Division Multiple Access) support wireless multimedia telephony services that include packet-switched transmission of data, such as images, text, documents, animations, audio files, video files, etc., in addition to traditional circuit-switched voice calls.

[0003] Recently, a network architecture called "IP Multimedia Subsystem" (IMS) was developed by the Third Generation Partnership Project (3GPP - 3 rd IMS (Integrated Multi-Generation Partnership Project) was developed to provide multimedia services for mobile and fixed clients in the packet domain. IMS is generally a platform for multimedia services based on IP transport, more or less independent of the access technology used. In principle, all types of access networks with packet-switching capabilities can be connected to an IMS network, including networks based on GPRS / UMTS, WLAN, fixed broadband, cable television, DSLAM, Ethernet, etc. The concept of IMS networks is well known in the field of telecommunications, and the different functions of the IMS network elements do not need to be described here to understand the present invention.

[0004] A specification for session initiation has been defined, called "SIP" (Session Initiation Protocol), which is an application-layer signaling protocol for controlling sessions via packet-switched logic. SIP is independent of the underlying data transport technologies and is generally used by session-managing nodes in IMS networks when supporting multimedia services.

[0005] One set of services that can be used via an IMS network are the so-called "presence" services. Presence services essentially involve publishing a user's "presence data" to make it available to other users and applications, which can then be used to control further services. Presence data essentially defines the state or situation of a user and their equipment in some predefined way.

[0006] The IMS architecture is based on a layered network structure, where different delivery functions are implemented in three main layers: an access layer, a session control layer, and a service layer. The services in the service layer are fundamentally independent of the technology and protocols used in the access layer. This layered architecture enables network convergence, as multiple different access networks, both fixed and cellular / mobile, can be connected to the same IMS session management layer, sometimes referred to as the "IMS core."

[0007] Some services in the service layer, as well as certain session management functions in the session control layer, may require or even necessitate information about the geographic location of a calling party. Examples of such services in IMS networks include presence services, messaging, and various information services, including GIS (Geographic Information System), presence-enabled friend lists, regionally sourced Yellow Pages, and the Friend and Family Finder function. Furthermore, setting user policies, billing rates, and other transmission parameters may also depend on the user's current location.

[0008] Location information can be particularly important for contacting subscribers in emergency situations, such as accidents and illnesses. An emergency call is typically first routed to an emergency center, which then connects the caller, depending on the current situation, to a local service station or similar, e.g., a doctor, a hospital, the fire department, or the police.

[0009] The requirements for emergency services are subject to regulations that vary across different countries and regions. Typically, the telephone system must be able to provide relevant location information to ascertain the caller's location. First, an incoming emergency call should be connected to an appropriate emergency response center located relatively close to the caller, known in the US as a Public Safety Alarm Point (PSAP), which can be critical in some situations. Second, the user might, for whatever reason, be unable to provide accurate location information to the emergency response center or service station, at least not immediately, which can be crucial for initiating further action quickly.

[0010] Fig. 1 represents a subscriber terminal A, which is connected to a conventional fixed telephone network 100 via a local exchange LE 102. The network 100 routes an incoming emergency call from subscriber A to an emergency center 104. The network 100 further includes a location database 106, which contains geographic location information about subscribers permanently connected to the network 100, including subscriber A, e.g., in the form of local street addresses or similar information.

[0011] In fixed, public networks, it is typically required that local exchanges ensure that a "caller identifier" is included in emergency calls when they are routed to an emergency call center. In this example, local exchange 102 knows of a subscriber terminal A, which is connected to a specific input line at exchange 102 that is associated with a particular caller identifier. Local exchange 102 therefore routes the caller identifier of subscriber terminal A to the emergency call center 104 when the emergency call is transmitted. A location database 106 stores the geographic location associated with the caller identifier.The emergency center 104 can therefore retrieve the location from the location database 106 using the identifier of the calling party that is linked to the emergency call, as shown by the dashed arrows.

[0012] In a cellular network, a mobile switching center (MSC) can include location information in emergency calls from mobile devices. This location information can be a cell identity (ID) or even more precise information in the form of geographic coordinates derived by positioning functions used in the network. A mobile positioning system (MPS) is often implemented in mobile networks, for example, using signal strength and / or timing measurements on signals from different base station sides, known as triangulation, to calculate a mobile device's position. The location information can be sent once in an emergency call or continuously updated during the call if the calling device moves.

[0013] Alternatively, a satellite-based navigation system, such as GPS (Global Positioning System) or Galileo, can be used. The terminal device must then, of course, be equipped with a GPS receiver capable of receiving satellite signals. Furthermore, the terminal device must have a function to transmit the position determination result in a comprehensive and secure manner to a session node, which handles the call in the session management layer. Dedicated positioning systems, such as GPS, typically require some time to determine the position, even several minutes. Local regulations often define a maximum permissible delay for providing the location to the emergency response center, usually within a few seconds.

[0014] Today, different methods for determining location are available in different types of access networks.

[0015] For example, if a private LAN (Local Area Network) is connected to an endpoint of a public access network, several new endpoints are effectively introduced within the LAN. Therefore, the geographic location of specific endpoints within the LAN is typically unknown to the public network unless they are specifically reported to the public network for storage in a location database or similar system.

[0016] Fig. Figure 2 schematically depicts three basic types of wired access networks used today for IP-based broadband access, connected to a backbone network 200, such as the Internet. A first network type 202 is connected to a backbone network 200 via a gateway 202a and is based on DSL (Digital Subscriber Line) technology. A switching node 202b, referred to as a DSLAM (DSL Access Multiplexor), is connected to a multitude of individual, dedicated subscriber lines, each of which uses a DSL-type modem (modulator / demodulator) 202c (e.g., ADSL) to modulate signals from one or more connected IP terminal devices onto a conventional two-wire copper wire, i.e., telephone wire. The DSLAM node 202b converts the modulated signals received on each subscriber line into Ethernet speech and vice versa.

[0017] A second network type 204 is similarly connected to a backbone network 200 via a gateway 204a and is based on cable television technology using coaxial or HFC (hybrid fiber coax) antenna cables. A switching node 204b, designated as a CMTS (Cable Modem Termination System), is connected to a common TV cable 204c, to which a multitude of cable modems 204d are connected for modulating signals from connected IP end devices onto the TV cable. The CMTS node 204b converts modulated signals received on the common TV cable 204c into Ethernet and vice versa. The location of the specific endpoints is typically unknown unless such information is added at the endpoints.

[0018] Typically, a third network type 206 is also known, which is shown connected to the backbone network 200 via a gateway 206a, based entirely on Ethernet transmission technology. A large number of switching nodes 206b are connected in a grid-like structure. Furthermore, a large number of IP end devices 206c are shown connected to at least some of the switches 206b. It should be mentioned that the three access network types are presented here merely as basic examples of network architectures that can be combined in any suitable way. It is also possible, for example, to create a DSL-type network using coaxial or HFC cables in the physical transport layer.

[0019] In this description, the network types mentioned above are each referred to simply as "DSL network," "cable network," and "Ethernet network." However, these access technologies more or less share the problem of obtaining reliable geographical information for callers using mobile devices, and there are currently no built-in functions for this purpose.

[0020] Even if an endpoint can be distinguished from others, each known endpoint must somehow be linked to location information, such as a street address, geographic coordinates, or similar. This requires maintaining a location database suitable for the known endpoints. Typically, the subscriber must provide mapping information for a currently used network address, e.g., a Layer 2 IP address, and a corresponding location, e.g., a street address, for storage in the location database. It is therefore impossible to validate that the stored mapping information is correct for every call, especially if subscribers move between different endpoints. Consequently, maintaining a location database is costly and still not entirely reliable.

[0021] Therefore, the problem of determining the location of a terminal device connected to a more or less fixed endpoint in a broadband network lies in certifying the location of that endpoint. Additionally, the obtained location information sometimes needs to be used to route the call to the appropriate party, especially in the case of emergency calls. This also needs to happen quite quickly, ideally within a few seconds, which is often subject to regulations. It may also be desirable to certify a location obtained through a process involving a terminal device that is not entirely trustworthy, for example, regarding its functionality or authenticity.

[0022] With regard to the above description of the prior art, it is desirable to provide reliable location information in a call from a caller connected to an access network, e.g., according to any of the network types described above. It is particularly desirable to obtain reliable location information for emergency calls in a reasonably fast manner, e.g., to meet prevailing emergency needs. It is also desirable to enable the rapid selection of a suitable emergency center to which an emergency call should be forwarded, depending on the caller's location.

[0023] Using an IMS network with separate access and session management layers that support multiple access network types (IP networks), for example, using newly designed access technology and protocols, it is not apparent how to provide a location to calling parties in a sufficiently fast and reliable manner. The challenge lies both in how to perform the location determination and how to validate its reliability. Furthermore, the situation can become even more complex when multiple different network operators are involved. The operator of an access network is not necessarily, and in fact often is not, the same as the operator of the IMS network, including the IMS core.

[0024] For example, a problem with existing solutions for fixed broadband networks is that in many access network types, such as cable or Ethernet networks, existing location solutions rely on pre-stored location information originally provided by the end users themselves, with no or very limited control mechanisms. Therefore, it is problematic that the network operator, who is typically responsible for correctly routing emergency calls according to regulations, cannot verify the accuracy of a caller's location provided by an access network if the access network depends on end-user-provided, i.e., "unreliable," location information.

[0025] Another problem is that even within a single access network, location can often be obtained in different ways with varying degrees of reliability. For example, in the case of a mobile access network, a user client on the mobile device might be configured to add the identity of the current cell to a header field, such as an existing header field called "P-Access-Network". However, a mobile device cannot always be trusted, as it can be infected by viruses or otherwise malfunction in a way that affects the aforementioned functionality.

[0026] A microcell-beacon-supported positioning method is known from WO 2005 / 106523 A1. Using local data communication technologies via radio, such as Bluetooth or WiFi, location and / or identification information is transmitted to mobile stations, which can be used to determine the mobile station's location. This is intended to improve the accuracy of positioning solutions in a large-area positioning system, such as a GPS system, an AFLT system, or a hybrid system.

[0027] US Patent 5,608,410 A discloses a system for determining the location of a mobile transmitter. The system comprises a database subsystem at the respective antenna locations and a database subsystem at a central location. SUMMARY

[0028] It is an objective of the present invention to address at least some of the problems described above and to provide a solution for obtaining more reliable location information for a communication terminal connected to an access network, e.g., for forwarding and / or routing to an emergency center in connection with an emergency call. These objectives and others can be achieved by providing a method and device according to the attached independent claims.

[0029] According to one aspect, the present invention provides a method for providing a reliable location for a communication terminal. In the method according to the invention, a first location for the terminal is obtained by means of a first access mechanism. A second location is also obtained for the terminal by means of a second access mechanism, and the obtained first and second locations are then compared. The location of the terminal is validated as reliable if the first and second locations are found to be substantially the same.

[0030] The validated location can be used and / or stored to support any service(s) that need or require that location. The validated location can further be stored in a location server or database on a communications service network serving the terminal device, and can then be displayed or marked as validated on the location server or database using an appropriate term such as "reliable," "confirmed," "certified," "verified," "validated," or similar.

[0031] The first and second access mechanisms can be used in different access networks, and the validation process can be triggered when a re-registration message is received from the endpoint after a handover from an old access network to a new one. The old access network can be a fixed-endpoint access network, and the new access network can be a mobile / cellular network, or vice versa. The validated location of the endpoint can then be further used to validate the location of an endpoint used by the endpoint in the fixed-endpoint access network. The fixed-endpoint access network can be a WLAN with user-provided endpoint locations, and locations in the mobile / cellular network can be obtained from cell IDs or via a triangulation procedure.

[0032] It is also possible that the first and second access mechanisms are used within the same access network.

[0033] Different positioning methods can be used in the first and second access mechanisms to obtain the first and second locations, respectively. The validated location of the terminal device can then be used to validate at least one of the positioning methods.

[0034] If the obtained first and second locations are not found to be substantially the same, new locations can be obtained alternately using the first and second access mechanisms, and each newly obtained location is then compared with the previously obtained location until the location is finally validated if it is substantially the same according to both the first and second access mechanisms.

[0035] Alternatively, a new pair of locations for the terminal can be obtained using the first and second access mechanisms, and the obtained new pair of locations is compared to validate the terminal's location if found to be substantially the same.

[0036] The locations being compared can be considered essentially equal if the difference between them does not exceed a predetermined equality criterion. If these essentially equal locations differ within the predefined equality criterion, an average of the essentially equal locations can be calculated as the validated location, or one that is considered more reliable than the other can be selected as the validated location.

[0037] According to another aspect, the present invention provides an arrangement for providing a reliable location for a communication terminal. The arrangement according to the invention comprises a device for obtaining a first location for the terminal by means of a first access mechanism, a device for obtaining a second location for the terminal by means of a second access mechanism, a device for comparing the obtained first and second locations, and a device for validating the location of the terminal as reliable if the obtained first and second locations are found to be substantially the same.

[0038] The arrangement may further include a device for using and / or storing the validated location to support any service(s) that need or require the location, and a device for storing the validated location by storing it in a location server or database in a communications services network serving the terminal device. The arrangement may then further include a device for displaying or marking the validated location as validated in the location server or database.

[0039] The arrangement may further include a device for using the validated location of the terminal device to validate the location of an endpoint used by the terminal device in an access network with fixed endpoints.

[0040] The arrangement may further include a device for using different positioning methods in the first and second access mechanisms, respectively, to obtain the first and second locations, and a device for using the validated location of the terminal device to validate at least one of the positioning methods.

[0041] The arrangement may further include a device for obtaining new locations alternately by means of the first and second access mechanisms if the obtained first and second locations are not found to be substantially the same, and a device for comparing each newly obtained location with the previously obtained location until the location is finally validated if it is substantially the same according to both the first and second access mechanisms.

[0042] The arrangement may also include a device for obtaining a new pair of locations for the terminal device by means of the first and second access mechanisms if the obtained first and second locations are found to be substantially the same, and a device for comparing the obtained new pair of locations in order to validate the location of the terminal device if they are found to be substantially the same.

[0043] The arrangement may further include a device for calculating an average value of the compared, substantially similar locations as the validated location, or for selecting one that is considered more reliable than the other as the validated location if the two compared locations differ within a predefined equality criterion.

[0044] Further features and advantages of the present invention will become apparent from the description below. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The present invention will now be described in greater detail and with reference to the accompanying drawings, in which: - Fig. 1 is a schematic block diagram of a fixed communication network according to the state of the art, which provides location information for an emergency call. - Fig. Figure 2 is a schematic block diagram illustrating three different, conventional network types for fixed broadband access according to the state of the art. - Fig. 3 is a schematic diagram illustrating one way of providing a more reliable location for a communication terminal device according to the present invention. - Fig. 4 is a schematic diagram that represents an embodiment for providing a validated location for a communication terminal device. - Fig. 5 is a flowchart that represents a procedure for providing a validated location for a communications terminal device, typically performed by a location server or similar in a communications services network. - Fig. 6 is a block diagram that represents a detailed scenario according to further embodiments where the location of a communication device can be validated. DETAILED DESCRIPTION

[0046] In short, the present invention enables a more reliable determination of the location of a communication terminal device that can be used to support communication services that need or require such location information, such as, in particular, emergency services.

[0047] An explanation will now generally refer to Fig. 3 described, in which an end device A is connected to a service network 300 containing a local server 302. In this general embodiment, the service network 300 represents any fixed or mobile network that provides communication services to an end device A, including services where the location of an end device A is required or may even be necessary, e.g., emergency services, as exemplified in the prior art section above. For example, a service network 300 could be an IMS network to which a plurality of separate access networks as described above may be connected.

[0048] The 302 location server is configured to retrieve and maintain the current location of an endpoint A in order to provide this information, if necessary, in connection with calls involving endpoint A, or if the location of endpoint A is required for any third-party services, such as when the current location of endpoint A is available to other users / applications, for example, for presence services. For instance, the location of endpoint A can be used immediately to route an emergency call from it to the correct emergency center, etc. Therefore, a 302 location server is configured to track the location of an endpoint A when it is registered as present on the 300 network, and if an endpoint A changes its location, the 302 location server should be updated accordingly.

[0049] As mentioned above, some types of access networks use positioning methods that can be considered more or less "reliable," such as mobile networks that use triangulation and certain fixed-end access networks that have certified the position of their endpoints, e.g., DSL networks. However, other network types may use positioning methods that are considered "unreliable," such as mobile networks that use cell ID, which may not be sufficiently accurate in large cells, or cable and Ethernet networks that depend on user-provided location information. The present invention aims to generally increase the reliability of positioning for such access networks.

[0050] In the Fig. In the embodiment shown in Figure 3, a first location L1 of an end device A is determined by means of a first access mechanism 304, which is schematically depicted in the figure and is provided to the location server 302. In this context, the term "access mechanism" should be understood in a broad sense to represent any technology or method that can be used to derive the location of an end device, including from cell ID and triangulation methods in mobile networks, as well as stored location information (e.g., user-provided) for fixed endpoints or access points in access networks, etc.

[0051] If the first location L1 is deemed unreliable, a second location L2 is determined using a second access mechanism 306, which is also provided to the location server 302. If the two determined locations L1 and L2 are found to be substantially the same, the location of terminal A is thereby validated, even if each location L1 and L2 themselves could be considered unreliable. The validated location obtained in this way for terminal A can now be used for any services and / or calls where it is needed or required.

[0052] Furthermore, if the endpoint is connected to a specific fixed access point or endpoint in an access network, such as a Wi-Fi network, the validated location of endpoint A can also be used to validate the location of that access point or endpoint in general, i.e., even when other endpoints connect to it. For example, if a location database for fixed endpoint locations (typically user-provided) is maintained in the network, the validated location obtained above for endpoint A can be displayed or marked within it as a validated, i.e., "reliable," location for the endpoint itself, which is currently being used by endpoint A. If any other endpoint subsequently makes a call or starts a session from that endpoint, the reliable location can be retrieved from the location database, which, being marked as validated / reliable, does not need to be revalidated.to support that call or that meeting.

[0053] Furthermore, the location validation procedure described above for end devices can also be used to validate a location determination mechanism in general. For example, if a particular location determination mechanism in a network has proven successful for a number of location validations, that mechanism can then be considered "reliable" for further location determinations, e.g., within a specific area, and can be relied upon in the future without validation by another location determination mechanism. In this context, it is also possible to assign a specific "trust" value to a location determination mechanism.For example, a “confidence” value could be: “the resulting location is expected to be correct with a probability of 99%”, or “the resulting location is expected to be correct within 100 m with a probability of 99%”, or something similar.

[0054] In this description, the term "reliable" is used to mark a location obtained (for a terminal device, a fixed endpoint, or a positioning mechanism) when that location has been validated by matching it in two different access mechanisms as described above. However, it should be noted that any other suitable term can be used to indicate that a location is validated in a location database or similar system, such as "confirmed," "certified," "verified," "validated," etc. Similarly, a location that has not been validated can be marked as "unreliable" or any other term with the same effect, such as "unconfirmed," "not verified," "not validated," etc.

[0055] To perform the location validation of terminal device A described above, the two different access mechanisms 304, 306 can be selected in several ways according to further embodiments, which will be described in greater detail below. Furthermore, access mechanisms in different access networks or different access mechanisms within the same access network can be used to determine the position of a terminal device, and the present invention is not limited to any specific access mechanisms. For example, the first access mechanism can comprise a positioning method in a cell of a mobile network, and the second mechanism can use the same positioning method as the first access mechanism, but in a different cell within the range of the terminal device.

[0056] If the determined locations L1 and L2 are found to be completely different, a third location can be derived, at least to a predefined extent, using either of the first and second access mechanisms 304, 306, this time using a higher level of accuracy compared to determining the previous locations L1 or L2. This process can be repeated alternately for the two access mechanisms 304, 306, until locations determined using the two access mechanisms are each found to be substantially the same, e.g., within a certain predefined boundary. At that point, the location of terminal A is confirmed or "validated" and can therefore be considered reliable for use in supporting any communication service(s) that need or require the location of terminal A.The validated location is ultimately stored by a memory in a location server 302 or, more generally, in a database accessible to it.

[0057] As mentioned above, this location validation can also be used to determine a reliable location for a network endpoint itself, to which device A is connected. This location can then be used for other devices that subsequently connect to that endpoint. The validated location of that endpoint can then be marked as "reliable" in the location database (e.g., on location server 302) to indicate that no further validation is required for that endpoint when other devices connect to it. Furthermore, it is also possible to display the accuracy of the stored endpoint location, e.g., within 100 m, depending on the accuracy of the positioning method used in the validation access mechanism. The displayed location accuracy may or may not be sufficient, depending on the requirements of the service used by a device connected to the endpoint.If not, the position of the terminal device can be determined further to obtain the required accuracy.

[0058] Therefore, new attempts at location validation for an end device can be performed using two different access mechanisms alternately at increasingly high accuracy levels until the location is finally validated by being equal according to both access mechanisms (304, 306). As mentioned previously, several different positioning methods are often available, e.g., the cell ID method and different triangulation methods of varying accuracy in mobile or cellular networks. The process of alternating location determination using different access mechanisms is schematically shown in Fig. 4 is shown involving two separate access mechanisms 400 and 402, which are used by a communication device A.

[0059] At a first accuracy level, designated "Level 1," locations L1 and L2 are determined using access mechanisms 400 and 402, respectively, with each location L1 and L2 considered uncertain in itself. Locations L1 and L2 are then compared and found not to be equal in this example, e.g., according to a certain predefined accuracy, hereinafter referred to as an "equality criterion." Therefore, a new pair of locations L3 and L4 is determined using access mechanisms 400 and 402, preferably using a higher, second accuracy level, "Level 2." Since the newly determined locations L3 and L4 are also found not to be equal when compared, another pair of locations L5 and L6 is determined in the same way, using an even higher, third accuracy level, "Level 3."In this case, locations L5 and L6 are indeed equal, thus validating the location of terminal A, and the resulting location is ultimately stored in a 404 location server. If the two most recently determined locations L5 and L6 still differ somewhat, although within an acceptable limit (i.e., a predefined equality criterion), an average value can be used for storage, or one considered more reliable than the other can be selected for storage.

[0060] In a slightly modified procedure, each newly determined location can be compared with the previously determined location in such a way that, after locations L1 and L2 have been determined to be unequal, a location L3 is determined and compared with L2. If L2 and L3 are then unequal, a location L4 is determined and compared with L3. If L3 and L4 are still unequal, a location L5 is determined and compared with L4, and so on. The location of terminal A can then be validated as soon as two compared locations are determined to be equal.

[0061] As in the example shown, the procedure for validating the location of terminal device A by comparing locations derived from two different access mechanisms is preferably performed by a location server or similar entity in a communication services network to which terminal device A is connected or which it belongs, e.g., an IMS network. Alternatively, this validation procedure can be implemented in the terminal device itself, in which case the terminal device ultimately sends the validated location to the location server for use and / or storage. Naturally, it is then assumed that the terminal device is equipped with suitable functionality that can be considered trustworthy for such location validation.

[0062] Fig. Figure 5 is a flowchart outlining the steps in a procedure for providing a validated location for a communication terminal device. This flowchart can also be used, for example, to validate a fixed endpoint in an access network or even to validate a positioning mechanism in general, as described above. For example, the following procedure can be used for the [unclear text] in [unclear text]. Fig. The embodiment shown in Figure 4 is used. In a first step 500, a first location for the terminal device is found by means of a first access mechanism, e.g. using a positioning method in an access network to which the terminal device is currently connected.

[0063] In the next step, 502, it is determined whether the initial location obtained can be considered reliable. If so, in step 504, the reliable location is stored and / or used depending on the nature of the connection and / or service requirements. The obtained, reliable location can be stored on a location server or similar and can also be used immediately or later to support any communication service(s) that require or may require the location of the terminal device. For example, if the terminal device is a fast-moving mobile device, it may not be necessary to store the obtained location for later use if it is not needed immediately, as it will quickly become outdated.On the other hand, if the terminal device is connected to a fixed endpoint in an access network, the received location can be saved as a validated endpoint location for later use when other terminal devices are connected to it.

[0064] However, if the first location in step 502 cannot be considered reliable, a second location is obtained in a subsequent step 506 using a second access mechanism. This second mechanism may employ a different positioning method in the current access network or any positioning method in a different access network than the one connected. For example, the terminal may have undergone a handover or a generally changed connection to a different network at any point between steps 500 and 506. Alternatively, the terminal may be forced to establish a connection to the other access networks, at least temporarily, for the purpose of obtaining the second location.Depending on the access capabilities of the terminal device, it can do this without losing a connection to the originating network, or it can return to it immediately after the second location has been obtained.

[0065] In a further step 508, the obtained first and second locations are compared to determine whether they are more or less the same to a predetermined extent. A certain acceptable range of difference may have been predefined in this respect. The condition or criterion for declaring the two locations to be the same may be defined in various ways, although the present invention is not limited in this respect. The equality criterion may be defined based on the expected accuracy of the positioning method and access mechanism used and / or a confidence level associated with the positioning method, etc.

[0066] If the received first and second locations are the same, for example, according to a predefined equality criterion, the location is validated, as indicated by step 510, and can be considered reliable, even if the received first and second locations cannot be considered reliable on their own. In that case, the procedure can proceed to step 504, where the validated location is stored and / or used to support any communication service(s) if needed or required immediately or in the future. As mentioned previously, the reliable location is stored and / or used depending on the nature of the connection and / or service requirements. In some cases, the location may be needed immediately, for example...in case an emergency call is received by the terminal device, which is to be forwarded to a suitable emergency center that is reasonably close to the calling terminal device and which may also require that the location information be provided along with the call.

[0067] As mentioned above, the obtained, reliable location can also be used to validate an endpoint in an access network or even to validate a positioning mechanism in use. In one possible implementation, two separate location databases can be maintained: a first database containing locations associated with individual endpoints / users, and a second database containing locations associated with fixed endpoints and / or positioning mechanisms with assigned trust values.

[0068] However, if the first and second locations are determined to be the same in step 508, the procedure continues as follows. If the result of step 508 is negative, the location can still be stored (not shown here), but should then be marked as "unconfirmed" or the equivalent to indicate that the stored location needs to be validated to be considered reliable.

[0069] Therefore, the procedure now continues by obtaining a third location using either the first access mechanism in step 500 or, alternatively, the second access mechanism in step 506, as indicated by a dashed arrow. Depending on the implementation, a fourth location may also be obtained using either the second or the first access mechanism, depending on the preceding step, to be compared with the third in step 508. Optionally, the third location obtained in either step 500 or 506 may be compared with the second or first in step 508 to determine whether it is necessary to continue obtaining the fourth location if they are not equal. Therefore, if the procedure is repeated, i.e., after the comparison step 508 has shown no equal, the sequence of steps 500-508 may be varied in any suitable way, depending on the implementation.For example, each new location obtained can be compared with the immediately preceding one if two access mechanisms are used alternately, as above in conjunction with . Fig. 4 explained.

[0070] Implementations useful for further deployments in different cells are described in greater detail below. For example, if the terminal device to be located is connected to an IMS network, a validation procedure can be triggered by various IMS events that occur when the terminal device changes connections between different access networks or re-establishes a session using a new access network, and possibly also when a user changes the terminal device to a different terminal device.

[0071] Such IMS events typically include various SIP messages designated as "REGISTER," "DE-REGISTER," "RE-REGISTER," "THIRD PARTY REGISTER," and "EVENT REGISTER," as well as other SIP messages. The validation process can also be initiated separately from the activities described above. The SIP messages can then be used to trigger the location validation process described above and to transport the resulting validated location to a receiving party, i.e., using "piggybacking."

[0072] The validation procedure can also be performed when the location is determined in two or more different access networks, in order to validate the location or a positioning mechanism used in at least one of them.

[0073] In an exemplary situation that occurs in Fig. As shown in Figure 6, a terminal device A, which is to be located, is connected to an IMS core 600 in the subscriber's "home" IMS network using terminal device A. Various access networks 602 of different types, sometimes referred to as "IP-CANs" (IP Connectivity Access Networks), are connected to the IMS core 600, and the terminal device can use at least some of these to access the IMS network. In the session control layer of the layered IMS system, session and user management takes place in the IMS core 600 using various, well-known CSCF (Call Session Control Function) nodes, which are briefly described here.

[0074] The P-CSCF (Proxy CSCF) node 604 generally serves as an entry point for end devices to the IMS network. Therefore, the access networks 602 are connected to the P-CSCF node 604 via border gateways (not shown). The P-CSCF node 604 forwards SIP messages between an end device and an S-CSCF (Serving CSCF) node 606 in its home IMS network, which handles session establishment between end device A and any called communication services 608 at the service layer. These services may be implemented in application servers or similar. The I-CSCF (Interrogating CSCF) node 610 is generally used by the P-CSCF node 604 to locate the correct S-CSCF node for a given user.Furthermore, a main database element HSS (Home Subscriber Server) stores 612 subscriber and authentication data that any application server and S-CSCF node can retrieve to run services and sessions for users.

[0075] When a user registers on the IMS network—that is, when they switch on their IMS terminal, plug in an IMS IP telephony terminal, or start an IMS-compatible client on their PC—information about the access network the user is currently connected to is stored in the HSS database. In the Fig. In the example shown in Figure 6, an end device A is initially connected to an IP-CAN 1 and this information is stored in an HSS database 612 when an end device A registers on the IMS network.

[0076] If the user changes their connection to a different access network, for example, when switching from a mobile network to a wireless LAN network or vice versa, a re-registration in the IMS network is performed for the user, which includes updating the access network information in the HSS database 612. Here, terminal device A changes its connection from IP-CAN 1 to IP-CAN 2, which is accordingly stored in HSS 612. This procedure can be used to validate the terminal device's location by obtaining locations in both access networks, IP-CAN 1 and IP-CAN 2.

[0077] Location validation can be triggered in various ways. To minimize the impact on existing routines, it can utilize a signal that is already being executed, such as registration signals of various forms. It can also be triggered by a signal to establish a session, when a notification is sent, or when presence data is updated. Location validation can also be actively initiated, for example, by the user or as part of an authorization procedure for a specific connection (e.g., a cable modem authorized to be used as a connection to the IMS).

[0078] For example, re-registration can trigger the acquisition of a new location in the new network to be compared with a location acquired in the previous network, with the latter preferably being marked as "unconfirmed" or similar when stored. If two acquired locations are identical, the location is validated and can be marked as "validated," "reliable," "confirmed," or any other appropriate term for that effect.

[0079] As described above, different methods and functions are available in the various access networks (602) to determine and represent the geographic location of a user terminal device. In mobile or cellular networks, these methods range from the relatively accurate A-GPS and various triangulation techniques to the simpler and less accurate cell ID method, the latter simply using the geographic coverage area of ​​a base station to represent a terminal device's location. The location accuracy then naturally depends on the cell size. Since the cell ID is a simple ID number, the mobile network operator must translate it into a geographic position in a format understandable outside the operator's network, e.g., given by latitude and longitude, and possibly also a suitable cell radius.

[0080] In fixed and wireless LAN networks, the location of an end device can be determined and represented in several different ways. Within ETSI (European Telecommunications Standards Institute), a working group called TISPAN (Telecom and Internet Services and Protocols for Advanced Networks) has been working on adapting IMS technology to fixed networks. A function called CLF (Connectivity Session Location and Repository Function) has been defined to map an IP address (and possibly also a MAC address) to a geographic address, such as a street address, latitude / longitude coordinates, or any other suitable geographic representation that can be used by IMS networks, primarily to provide location information for emergency calls. Fig. Figure 6 shows a CLF database 614 in the IMS kernel 600.

[0081] In many types of access networks, the information provided by the CLF function cannot be considered reliable. In DSL networks, where each endpoint has a dedicated and known physical network connection, the available location information can generally be considered reliable; however, this may not be the case in other networks. For example, in cable networks, it is usually not possible to certify the location of each endpoint, which typically relies on user-provided location information, as mentioned above. The situation is similar for Ethernet networks.

[0082] Some exemplary location validation procedures that can be used to implement the present solution are now described in greater detail and with further reference to Fig. 6 described.

[0083] As mentioned above, validation can be triggered by various registration methods using messages, such as Register, Re-Register, De-Register, 3D Party Register, or Event Register. When an IMS endpoint is powered on or when a client is started on an endpoint, the user and their endpoint are registered with the IMS core 600. A SIP Register message is sent from the endpoint via the P-CSCF node 602 to the S-CSCF node 606, informing the latter that the user / endpoint has been registered. The S-CSCF node 606 also sends a message to the HSS database 612.

[0084] A field in the header of the received SIP message is called "P-Access-Network" and can contain location-related information. If a mobile network is used for access, this field typically contains the cell ID, but it can also include other location-related information, such as measurement results that can be used in a triangulation calculation. Other fields or bodies can also be used to carry location information, including new, standardized header and / or body fields, or existing fields according to a standard or operator-defined usage and syntax.

[0085] When a registration is performed, the S-CSCF node, or possibly an E-CSCF (Emergency) node handling emergency calls, may forward the received registration message (modified or not) to other IMS units, which could be a location server or similar entity on the user's home network or possibly on a visiting network. Then, depending on the currently used access network, which can be identified by available routing information if not clearly stated in the registration message, the location server may decide to perform an active location determination on the terminal device to validate the location specified in the message header. In this case, the location in the header was indeed obtained via a first access mechanism (e.g., a connection to a serving cell), and the location of the active location determination is then obtained via a second access mechanism (e.g., a cellular network).a triangulation procedure) obtained, therefore according to the procedures used for . Fig. 3-5 are described.

[0086] It may also be possible to transmit information other than the device location to the location server for database storage to enable location validation. This information could include routing information, network information, and device information. Location validation can either utilize features within the currently used access network, or the device can be forced to temporarily change its access to a different network for validation, as mentioned above. Of course, the latter option is only possible if the device is within the coverage area of ​​the new network. Furthermore, location determination for validation can be performed without interrupting an access currently used for an ongoing IMS session if the device supports multiple parallel accesses, such as simultaneous connections to a wireless LAN and a mobile / cellular network.

[0087] When comparing locations obtained through two different access mechanisms, a valid location is preferably determined in the best possible way (e.g., in terms of feasibility, accuracy, response time, confidence, etc.), and it is also evaluated whether a location can be considered reliable. Furthermore, if no location information is available for a currently used network or network endpoint, a location can be obtained from one or more other networks.

[0088] As described above, the location of a used endpoint device can be validated according to this solution when a session / user is handed off from one access network to another. For example, in a broadband access network with fixed endpoints, validation of the location of an endpoint device, or alternatively of the network endpoint (a modem, router, or access point) to which it is connected, can also be performed when a session is handed off from that network to another, or vice versa. In this case, the location can be validated by comparing the last location obtained in the previous network with a new location obtained in the new network.

[0089] In one example, an endpoint is handed off during an ongoing session from, for example, a mobile / cellular network to a wireless LAN network. Validation can be performed by using location information that appears in the header of a SIP message in the ongoing session, or by using the RE-REGISTER message sent after a handover, or alternatively by using any other message that carries the location or other information (e.g., a cell ID) in any format that can be converted into a geographic location.

[0090] Two main options can then be used. One option is to validate the location in the new network (i.e., the given location of an endpoint or router) to which the endpoint is being transferred by comparing it to a stored location in the old network from which the endpoint is being transferred. In this case, the most accurate available location in the old network should be used. Another option is to validate the location in the old network by using the location in the new network. A combination of these two options can also be used.

[0091] The P-Access-Network header typically contains only information about the location within the network where the terminal is currently registered. As a result, the location server typically receives only a location within the network to which the terminal is handed off during a session, unless the location is continuously monitored and updated. In this case, the validation process is simple because the location within the network from which the handover occurs is known. The terminal can then be configured to store a location obtained in the old network, such as a cell ID, and add this to the RE-REGISTER message or any other appropriate message sent after handover to the new network.

[0092] Another way to achieve location validation in some situations is as follows. A user / device may be registered on an access network where the location cannot be verified (since verification cannot be performed on such an "unsecured" network, the verification is outdated or invalid for some other reason), either through a regular registration process or re-registration when the device is handed off to a new network. For example, a Wi-Fi-enabled mobile device may be handed off to a Wi-Fi access point from its mobile / cellular access point when the user enters their home environment. This network location, either an unverified geographic location or a network address with an untranslated location, can be marked as "unreliable" or "unverified" when stored in a location database or similar system.The next time the device connects to this Wi-Fi access point (i.e., the location marked as unreliable in the database), a new location is obtained from the network being connected to. This new location is then used to validate the unreliable location stored in the database, if they match. This process saves the location of that Wi-Fi access point, and the unreliable marker can be removed or changed to "reliable" or similar.

[0093] Another way to provide location information from an endpoint to a location server after a handover from an old access network to a new one, which can be used for location validation, is to populate the P-Access-Network field described above with both a location retained in the old network and a location retained in the new network. When registering in a new network, it can be useful to provide the location retained in the old network, since this network connection will be lost after the handover.

[0094] In addition to the examples described above, which involve a handover between different access networks, a validation procedure for the location of an endpoint may be performed in other cases, for example, when a new endpoint has been installed or authorized in an access network. Furthermore, a connection or endpoint sometimes needs to be verified to allow an endpoint and / or user to register with an IMS network.

[0095] As mentioned above, the validation process can be triggered by various events. For example, it can be triggered when a new address appears in the routing pass, or when a change in the routing pass from the IMS network to an endpoint is detected, or when the router or modem has been replaced or moved to a different location. It can also be triggered when it is detected that the service at an endpoint has been switched on or off, for example, when a DHCP (Dynamic Host Configuration Control) server or router indicates that the connection to the endpoint has been lost and then re-established. This can also be a standard procedure scheduled to perform validation periodically.

[0096] In further implementations, multiple devices and possibly also the end user can be actively involved to some extent in validating the location of an end device. For example, a wired connection of a first end device, e.g., with a MAC address, can be validated using a second end device connected to a mobile / cellular network. The first end device, or a client within it, can initiate the validation process using the cellular connection of the second end device. It can then be certified in some way that the mobile device and the wired end device are located in the same place, but this is outside the scope of the present invention.

[0097] For example, a predefined control code or similar can be displayed on the first device and entered into the second device. For this purpose, barcodes or similar codes can be displayed on the first device's screen (e.g., a computer). A local area network connection of limited range between the first and second devices can also be used, such as a Bluetooth or wireless LAN connection. By sending a confirmation message from the second mobile / cellular device and forwarding it to the first wired device, the location information of the first device can be validated. Furthermore, the location server can verify the message's journey, ensuring it passed through the first device by checking the routing paths and MAC addresses used by the connections.

[0098] The present invention, as described with reference to the various embodiments above, provides a simple yet reliable mechanism for obtaining more dependable location information for an end device connected to an access network. After validation according to the present invention, the location information can be used to support various communication services, if needed or required, for example, by supplying it to a called party and / or an application server or similar.

[0099] While the invention has been described with reference to specific, exemplary embodiments, the description is generally provided only to illustrate the inventive concept and should not be considered to limit the scope of the present invention. Furthermore, the invention is not limited to any particular services but can be used to provide location information for any type of communication service that requires such information. The present invention is defined by the attached claims.

Claims

[1] Method for providing a reliable location for a communications terminal device, comprising the following steps: - Obtaining an initial location for the terminal device via an initial access mechanism, - Obtaining a second location for the terminal device via a second access mechanism, where the first and second access mechanisms are used in different access networks; characterized by - Comparing the first and second locations obtained, and - Validating the location of the terminal as reliable if the first and second locations obtained are found to be substantially the same, where the validated location of the terminal device is used to consider at least one of the first access mechanism or the second access mechanism as reliable for further location determinations without validation from another access mechanism. [2] Method according to claim 1, wherein the validated location is used and / or stored to support any service(s) that need or require the location. [3] Method according to claim 2, wherein the validated location is stored by storing it in a location server or a database in a communication services network that serves the terminal device. [4] Method according to claim 3, wherein the validated location is displayed or marked as validated in the location server or database. [5] Method according to claim 1, wherein the old access network is a fixed endpoint access network and the new access network is a mobile / cellular network, or vice versa. [6] Method according to claim 5, wherein the validated location of the terminal device is used to validate the location of an endpoint used by the terminal device in the access network with fixed endpoints. [7] Method according to claim 5 or 6, wherein the access network with fixed endpoints is a WLAN with user-provided endpoint locations and locations in the mobile / cellular network can be obtained from cell IDs or by means of a triangulation method. [8] Method according to any one of claims 1-7, wherein different position determination methods are used in the first and second access mechanisms to obtain the first and second locations. [9] Method according to claim 8, wherein the validated location of the terminal device is used to validate at least one of the positioning methods. [10] Method according to any one of claims 1-9, wherein, if the first and second locations obtained are not found to be substantially the same, new locations are obtained alternately by means of the first and second access mechanisms and each new location obtained is compared with the previously obtained location until the location is finally validated if it is substantially the same according to both the first and second access mechanisms. [11] Method according to any one of claims 1-9, wherein, if the obtained first and second locations are not found to be substantially the same, a new pair of locations for the terminal device is obtained by means of the first and second access mechanism and the obtained new pair of locations is compared to validate the location of the terminal device if it is found to be substantially the same. [12] Method according to any one of claims 1-11, wherein the compared locations are found to be substantially the same if the difference between them does not exceed a predefined equality criterion. [13] Method according to claim 12, wherein, if the substantially identical locations differ within the predefined equality criterion, an average value of the substantially identical locations is calculated as the validated location, or one that is considered more reliable than the other is selected as the validated location. [14] Arrangement for providing a reliable location for a communications terminal device, comprising: - a device for obtaining a first location for the terminal device by means of a first access mechanism, - a device for obtaining a second location for the terminal device by means of a second access mechanism, where the first and second access mechanisms are used in different access networks; characterized by - a device for comparing the obtained first and second locations, and - a device for validating the location of the terminal as reliable if the first and second locations obtained are found to be substantially the same, where the validated location of the terminal device is used to consider at least one of the first access mechanism or the second access mechanism as reliable for further location determinations without validation from another access mechanism. [15] Arrangement according to claim 14, further comprising a device for using and / or storing the validated location to support any service(s) that need or require the location. [16] Arrangement according to claim 15, further comprising a device for storing the validated location by storing it in a location server or a database in a communication services network serving the terminal device. [17] Arrangement according to claim 16, further comprising a device for displaying or marking the validated location as validated in the location server or database. [18] Arrangement according to claim 14, wherein the old access network is a fixed endpoint access network and the new network is a mobile / cellular network, or vice versa. [19] Arrangement according to claim 18, further comprising a device for using the validated location of the terminal device to validate the location of an endpoint used by the terminal device in the access network with fixed endpoints. [20] Arrangement according to claim 18 or 19, wherein the access network with fixed endpoints is a WLAN with user-provided endpoint locations and locations in the mobile / cellular network can be obtained from cell IDs or by means of a triangulation method. [21] Arrangement according to one of claims 14-20, further comprising a device for using different positioning methods in the first and second access mechanisms respectively, to obtain the first and second location. [22] Arrangement according to claim 21, further comprising a device for using the validated location of the terminal device to validate at least one of the positioning methods. [23] Arrangement according to one of claims 14-22, further comprising a device for alternately obtaining new locations by means of the first and second access mechanism if the obtained first and second locations are not found to be substantially the same, and a device for comparing each new obtained location with the previously obtained location until the location is finally validated if it is substantially the same according to both the first and second access mechanism. [24] Arrangement according to one of claims 14-22, further comprising a device for obtaining a new pair of locations for the terminal device by means of the first and second access mechanism if the obtained first and second locations are not found to be substantially the same, and a device for comparing the obtained new pair of locations in order to validate the location of the terminal device if found to be substantially the same. [25] Arrangement according to one of claims 14-24, wherein the locations being compared are found to be substantially the same if the difference between them does not exceed a predefined equality criterion. [26] Arrangement according to claim 25, further comprising a device for calculating an average value of the compared, substantially the same locations as the validated location or for selecting one that is considered more reliable than the other as the validated location if the two compared locations are different within the predefined equality criterion.

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