EP1911198A2

EP1911198A2 - Methods and devices for supporting location services in a communication system

Info

Publication number: EP1911198A2
Application number: EP06820816A
Authority: EP
Inventors: Martin Thomson; James Winterbottom; Martin Dawson
Original assignee: Nortel Networks Ltd
Current assignee: Apple Inc
Priority date: 2005-06-29
Filing date: 2006-06-29
Publication date: 2008-04-16
Also published as: EP1911198A4; WO2007026250A3; WO2007026250A2

Abstract

A first aspect of an embodiment of the present invention provides a method of requesting location information. The method comprises the initial step of obtaining a datum that has been assigned to a computing device. Subsequent to the initial step the method involves the step of processing the datum to identify a location information system which assigned the datum to the computing device. Another step involved in the method is to provide the location information system with a location request, which is associated with the datum, for the location information .

Description

METHODS AND DEVICES FOR SUPPORTING LOCATION SERVICES IN A COMMUNICATION SYSTEM

Field of the Invention

[0001] The present invention relates generally to the field of location services for a communication system, and has particular - but by no means exclusive - application to an Internet Protocol based communication system.

Background of the Invention

[0002] Traditional telecommunication networks, such as a public switched telephone network (PSTN) , can be readily augmented with technology for facilitating location services. Location services essentially enable an entity to determine the geographic location of a calling party; that is, a party responsible for initiating a call via the telecommunication network.

[0003] While location services can have a range of applications, a particular example application is to emergency service networks such as 911 in the United States of America and 000 in Australia. In a typical emergency services network the location services basically facilitates routing of incoming calls to an appropriate emergency call centre for the jurisdiction covering the point of origin of the calls. Furthermore, the location services are used to present (on a computer monitor) the location of calling parties to emergency call centre operators .

[0004] An existing location services architecture employs a gateway router that takes calls from a public switched telephone network (PSTN) and, based on the calling line identifier, routes the calls to the appropriate emergency call centre for the jurisdiction covering the point of origin of the calls. The existing location services architecture also incorporates a subscriber database that stores data associated with a device from which a call originates (for instance, a fixed home telephone) . For example, the data could comprise the street address associated with the line subscription. Data contained in the subscriber database can be provided to a call recipient (for instance, an emergency services operator) based on a query key, which is typically the calling line identifier.

[0005] The association between the calling line identifier and the data contained in the subscriber database enables efficient and effective provisioning of location services in a PSTN. Unfortunately, however, the aforementioned location services architecture does not appear to be well suited to providing location services for non-traditional telecommunication systems such as mobile telephony and portable Internet Protocol (IP) enabled communication devices (for example, BlackBerry™ devices). Unlike a fixed telephone connected to a PSTN, mobile telephones and portable IP communication devices generally do not have an immediate association with a location that enables the existing location service architecture to route calls therefrom. The inherent mobility characteristics of mobile telephones and portable IP communication devices results in an absence of a specific physical point of connection that dictates the calling party's identity.

Summary of the Invention

[0006] A first aspect of an embodiment of the present invention provides a method of requesting location information. This method can be performed by, for example, a computer used by an operator in an emergency services call centre. In the embodiment of the present invention the location information comprises the location of a computing device in the form of, for example, a portable IP communication device. The method of requesting the location has the potential to facilitate location services for the computing device. More specifically, the method comprises the initial step of obtaining a datum that has been assigned to the computing device . Subsequent to the previous step the method involves the step of processing the datum to identify a location information system which assigned the datum to the computing device. Identifying the location information enables an entity to identify a system that can be queried for the location information pertaining to the computing device. Another step involved in the method is to provide the location information system with a location request, which is associated with the datum, for the location information. Thus, providing the location information system with the location request provides a mechanism for informing the location information system that the location information is required. In this regard, the fact that the location request is associated with the datum allows the entity to indicate to the location information system which computing device is of interest.

[0007] A second aspect of the embodiment provides a method of responding to a request for location information. In the embodiment of the present invention this method is performed by the location information system. The method is the manner in which the location information system responds to the location request. An initial step of the method involves receiving the location request, which is associated with the datum, for the location information. Following on from the previous step the method involves processing the datum to identify the computing device to which the location information system assigned the datum. Identifying the computing device is done to ensure the appropriate location information is retrieved. Subsequent to the previous step the method involves the step of issuing the location of the computing device, as per the request signified by the received request for location information.

[0008] A third aspect of the embodiment provides another method of responding to a request for a piece of information for use in requesting location information. In the embodiment of the present invention this method is performed by a presence information system in response to receiving a request to provide the datum. The request to provide the datum could, for example, be issued by an entity that wants to request the location information from the location information system but does not posses the datum that is to be associated with the request for location information. This method comprises the initial step of receiving a datum request, which informs the presence information system that the datum is required. After the previous step the method involves the step of processing the datum request to identify a computing device. In the embodiment of the present invention the datum request comprises an IP address of the computing device. The method also comprises the step of obtaining the datum that has been assigned to the computing device by a location information system. As a last step the method involves issuing the datum.

[0009] A fourth aspect of the embodiment provides another method of responding to a request for a piece of information for use in requesting location information. This particular method is performed by a pseudonym processing system and can be used to provide a level of privacy in relation to the actual identifier (for example, the IP address) of the computing device. The method comprises the initial step of receiving a datum request. Following on from the previous step is the step of processing the datum request to identify a pseudonym associated with a computing device. In the embodiment of the present invention the pseudonym is an encrypted version of the IP address of the computing device. After the preceding two steps the method involves the step of determining a verinym that is associated with the pseudonym. The verinym could be the unencrypted IP address of the computing device. At this stage, the method involves the step of providing the presence information system with a datum request that is associated with the verinym. In addition to the previous step the method comprises the step of receiving a reply from the presence information system. Subsequent to receiving the reply, the method includes the step of processing the reply to obtain the datum that has been assigned to the computing device by the location information system. The method also includes as a final step issuing the datum.

Brief Description of the Drawings

[0010] The present invention will be more fully understood from the following description of an embodiment with reference to the following drawings, in which:

[0011] Fig. 1 is a schematic diagram of a system including an embodiment of the present invention,-

[0012] Fig. 2 is a flow chart of various steps performed by the embodiment depicted in fig. 1;

[0013] Fig. 3 is a representation of a datum used by the embodiment of fig . 1 ,- and

[0014] Fig. 4 to Fig. 9 are flow charts of various steps performed by the embodiment depicted in fig. 1.

Detailed Description

[0015] With reference to fig. 1, which is a schematic diagram of a system 100 including an embodiment of the present invention, the system 100 comprises: an electronic computing device 102 that comprises a location services client 104; a location information system 106; a presence information system 108; a pseudonym processing system 110; a privacy system 112; a home subscriber server 114; a domain name server 116; one or more mobile electronic communication devices 118; an intra-network 120; an internetwork 122; and a signalling network 124.

[0016] The electronic computing device 102 is in the form of a personal computer that comprises traditional computer hardware such as processing hardware (for example, a microprocessor and random access memory) , a hard disk for storing computer programs and data, a keyboard, and a monitor. The electronic computing device 102 also comprises communication hardware and software for exchanging data via the inter-network 122. It is envisaged that in an alternative embodiment of the present invention the electronic computing device 102 is arranged to function as a 'broker' in the form of a Gateway Mobile Location Centre (GMLC) . Furthermore, persons skilled in the art will appreciate that the electronic computing device 102 could, in alternative embodiments of the present invention, be any form of suitable computing device.

[0017] The location services client 104, which forms part of the electronic computing device 102, is in the form of software that resides on the hard disk of the electronic computing device 102. The location services client 104 is essentially arranged to obtain, from the location information system 106, location information pertaining to the one or more mobile electronic communication devices 118. In the alternative embodiment in which the electronic computing device 102 is in the form of a GMLC, the location service client 104 would effectively obtain the location information on behalf of another electronic device (which is not shown in fig. 1) . [0018] The location information system 106 is in the form of a computer server that comprises traditional computer hardware such as processing hardware (for example, a microprocessor and random access memory) and a hard disk for storing computer programs and data. The hard disk of the location information system 106 is loaded with software that is arranged to provide the location services client 104 with the location information. The location information system 106 also comprises communication hardware and software for exchanging data via the intra-network 120 and the inter-network 122.

[0019] The presence information system 108 is in the form of a computer server that comprises traditional computer hardware such as processing hardware (for example, a microprocessor and random access memory) and a hard disk for storing computer programs and data. The hard disk of the presence information system 108 is loaded with software that is arranged to provide a datum 300 that the location services client 104 can use to obtain the location information from the location information system 106. In addition to the datum 300, the presence information system 108 is arranged to provide presence information such as the current status of the one or more mobile electronic communication devices 118. The presence information system 108 also comprises communication hardware and software for exchanging data via the inter-network 122.

[0020] The pseudonym processing system 110 is in the form of a computer server that comprises traditional computer hardware such as processing hardware (for example, a microprocessor and random access memory) and a hard disk for storing computer programs and data. The pseudonym processing system 110 is similar to the presence information system 108 in that the hard disk is loaded with software that is essentially arranged to provide the datum 300 that the location services client 104 can use to obtain the location information from the location information system 106. In addition to providing the datum 300, the pseudonym processing system 110 is also arranged to translate a pseudonym, which is associated with the one or more mobile electronic communication devices 118, in order to retrieve the appropriate datum 300. The pseudonym processing system 110 also comprises communication hardware and software for exchanging data via the inter-network 122.

[0021] The privacy system 112 is in the form of a computer server that comprises traditional computer hardware such as processing hardware (for example, a microprocessor and random access memory) and a hard disk for storing computer programs and data. The hard disk of the privacy system 112 is loaded with software that is arranged to manage privacy related information that the system 112 uses to advise the location information system 106 on whether the location information can be provided to the location services client 104. The privacy system 112 also comprises communication hardware and software for exchanging data via the inter-network 122.

[0022] The home subscriber server 114 is in the form of a computer server that comprises traditional computer hardware such as processing hardware (for example, a microprocessor and random access memory) and a hard disk for storing computer programs and data. The hard disk of the home subscriber server 114 is loaded with software that is essentially arranged to manage the personal setting

(such as selected call forwarding functions) for the users of the one or more mobile electronic communication devices 118. The home subscriber server 114 is also arranged to maintain data related to the current location of the one or mobile electronic communication devices 118. The home subscriber server 114 also comprises communication hardware and software for exchanging data via the signalling network - B -

124 .

[0023] The domain name server 116 is in the form of a computer server that comprises traditional computer hardware such as processing hardware (for example, a microprocessor and random access memory) and a hard disk for storing computer programs and data. The hard disk of the domain name server 116 is loaded with software that is arranged to translate an internet domain name in to an IP address. The domain name server 116 also comprises communication hardware and software for exchanging data via the inter-network 122.

[0024] The one or more mobile electronic communication devices 118 are in the form of a portable personal computer (such as a laptop or personal digital assistant) that comprise traditional computer hardware such as processing hardware (for example, a microprocessor and random access memory) , a hard disk for storing computer programs and data, a user input interface (for example a keyboard or key pad) and a visual display. The hard disk of the one or more mobile electronic communication devices 118 is loaded with IP technology software; for example, a Voice over IP (VoIP) application. The one or more mobile electronic communication devices 118 each comprise communication hardware and software for exchanging data via the intra- network 120.

[0025] The intra-network 120 and the inter-network 122 are in the form of IP based networks and as such each comprises interconnected packet routers/switches that are arranged to route/switch IP packets. On the other hand, the signalling network 124 is in the form of a Signalling System 7 (SS7) based network for performing out-of-band signalling.

[0026] As outlined previously, the location services client 104 is arranged to obtain location information pertaining to one or more mobile electronic communication devices 118. To obtain the location information the location services client 104 performs several steps, which are contained in the flow chart 200 of fig. 2. In this regard, the initial step 202 performed by the location services client 104 is to obtain a datum 300 that has been assigned to the mobile electronic communication device 118 of interest .

[0027] The datum 300 is in the form of electronic data, and as can be seen from fig. 3, comprises as least two fields 302 and 304. The first field 302 contains data that represents the public IP network address of the location information system 106, while the second field 304 contains data that represents a unique communication session identifier created by the location information system 106. An aspect of the datum 300 worth noting is that it does not necessarily contain any public information (such as an IP address) that identifies a mobile electronic communication device 118. The session identifier, while identifying the electronic computing device 102, is private information known to the location information system 106. It is, however, envisaged that in an alternative embodiment of the invention the second field 304 may well contain public information that identifies the electronic computing device 102.

[0028] Once the location services client 104 has obtained the datum 300, the next step 204 it performs is to process the datum to identify the location information system 106, which previously assigned the datum 300 to the mobile electronic communication device 118 of interest. The location service client 104 is arranged to identify the location information system 106 by examining the first field 302 of the datum which, as outlined previously, contains data that represents the public IP network address of the location information system 106.

[0029] Subsequently to identifying the location information system 106, the location services client 104 carries out the step 206 of providing the location information system 106 with an electronic location request message that comprises the datum 300. More specifically, the location services client 104 creates the electronic location request message and passes it to the communication hardware and software of the electronic computing device 102. In turn, the communication hardware and software encapsulates the electronic location request message in to an IP packet, which has a destination address field that corresponds to the public IP network address of the location information system 106 as contained in the first field 302 of the datum 300.

[0030] Once the communication hardware and software encapsulates the electronic location request message in to the IP packet, it transfers the IP packet to the internetwork 122. By virtue of the destination address field the inter-network 122 will forward the IP packet to the location information system 106. As discussed in more detail in the following paragraphs of this specification the location information system 106 may, on receipt of the IP packet from the location services client 104, respond with the location information for the mobile electronic communication device 118 of interest.

[0031] It is noted that the previous steps 204 and 206 are basically concerned with identifying a single computer server (the location information system 106) and sending the single computer server an electronic location request message. It is, however, envisaged that in an alternative embodiment of the present invention the location information system can include a plurality of computer servers. In this alternative embodiment, the step 204 could involve identifying one of the computer servers that assigned the datum 300 to the mobile electronic communication device 118. While the step 206 could include sending the electronic location request message to another of the computer servers that was not involved in assigning the datum 300 to the mobile electronic communication device 118.

[0032] As described previously, the location services client 104 performs the step 202 of obtaining the datum

300. The location service client 104 is arranged to obtain the datum 300 using several different techniques. A first of these techniques involves retrieving the datum 300 from a local cache memory of the electronic computing device 102. Retrieving the datum 300 from the local cache memory means that the location service client 104 has previously obtained the datum 300 and placed it in the cache memory for future use. If, however, the local cache memory does not contain the datum 300 the location services client 104 can attempt to obtain the datum 300 from the presence information system 108 or the pseudonym processing system 110.

[0033] To obtain the datum 300 from the presence information system 108 the location services client 104 is arranged to perform several steps, which are depicted in the flow chart 400 of fig. 4. In this regard, the first step 402 performed by the location services client 104 is to identify the presence information system 108 for the mobile electronic communication device 118 of interest.

Identifying the presence information system 108 basically involves obtaining the IP network address of the information system 108. It is envisaged that the presence information system 108 may not serve all of the mobile electronic communication devices 118; that is, the mobile electronic communication devices 118 may use different presence information systems 108. Consequently, the step 402 of identifying the presence information system 108 • ensures that the appropriate presence information system 108 is selected for the mobile electronic communication device 118 of interest.

[0034] The location services client 104 can identify the presence information system 108 using a variety of techniques. A first of these techniques involves sending, via the signalling network 124, a send routing info for location services message to the home subscriber server

114. The first technique is similar to that outlined in the 3GPP TS 23.271 technical specification. In response to receiving the send routing info for location services message, the home subscriber server 114 issues (via the signalling network 124) a response message that contains the address of a privacy profile register. The location services client 104 is arranged to interpret the address of the privacy profile register as the address of the presence information system 108. Alternatively, instead of interpreting the address of the privacy profile register as the address of the presence information system 108 the response message issued by the home subscriber server 114 can be extended to include a new field for the actual public address of the presence information system 108.

[0035] Another technique for identifying the presence information system 108 involves querying the domain name server 116, as per IETF drafts RFC3761 and RFC2915. Of course, this technique assumes the mobile electronic communication device 118 of interest is associated with a fully qualified domain name in accordance with IETF draft RFC1035. Querying the domain name server 116 involves providing the server 116 with either a fully qualified domain name or an E.164 number.

[0036] Once the location services client 104 has identified the presence information system 108, the location services client 104 proceeds to perform the step 404 of providing the presence information system 108 (which was identified by the previous step 402) with a first electronic datum request message. The first electronic datum request message comprises a device identifier, which is known to the presence information system 108, for the mobile electronic communication device 118. As an example, the device identifier could be the actual IP address of the mobile electronic communication device 118 of interest.

[0037] To provide the presence information system 108 with the first electronic datum request message the location services client 104 basically passes the datum request message to the communication hardware and software of the electronic computing device 102, which in turn encapsulates the first datum request in to an IP packet. The destination address field of the IP packet is set to the IP network address of the presence information system, which was obtained during the previous step 402. Once the communication hardware and software has created the IP packet it transfers the packet to the inter-network 122, which delivers the IP packet to the presence information system 108 for processing.

[0038] As described in detail in the subsequent paragraphs of this specification, the presence information system 108 can respond to the first datum request message by sending the location services client 104 a first electronic reply message via the inter-network 122. The first electronic reply message comprises the datum 300 for the mobile electronic communication device 118 of interest and is issued via the inter-network 122. Consequently, to obtain the datum 300 from the presence information system 108 the location services client 104 performs the step 406 of receiving the first electronic reply message via the inter-network 122. After the previous step 406 the location services client 104 performs the step 408 of processing the first electronic reply message to obtain the datum 30Oi Given that the first electronic reply is received via the inter-network 122, the step 408 of processing the first electronic reply message involves initially retrieving the first electronic reply message from the IP packet that encapsulated the reply message.

[0039] As described previously the location services client 104 is, in addition to being arranged to obtain the datum from the presence information system 108, arranged to obtain the datum 300 from the pseudonym processing system 110. Obtaining the datum 300 from the pseudonym processing system 110 involves several steps, which are shown . in the flow chart 500 of fig. 5. The first 502 of these steps involves obtaining a pseudonym that is associated with the mobile electronic communication device 118 of interest . For example, the pseudonym might be an encrypted identifier (for example, encrypted IP address) of the mobile electronic communication device 118 of interest . Use of the pseudonym effectively provides a means for maintaining a level of privacy for the mobile electronic communication devices 118.

[0040] Following on from the previous step 502 the location services client 104 carries out the step 504 of providing the pseudonym processing system 110 with a second electronic datum request message, which comprises the pseudonym. This step 504 initially involves creating the datum request message and then passing it to the communication hardware and software (of the electronic computing device 102) , which encapsulates the request message in an IP packet. The communication hardware and software transfers the IP packet to the inter-network 122, which sends the packet to the pseudonym processing system 110.

[0041] The pseudonym processing system 110 is arranged to respond to the second electronic datum request message by sending, via the inter-network 122, a second electronic reply message. The second electronic reply message comprises the datum 300 for the mobile electronic communication device 118 of interest. Consequently, the location services client 104 is arranged to perform the step 506 of receiving the second electronic reply message. The step 506 of receiving the second reply message comprises extracting the second reply message from an IP packet used to transfer the reply message via the internetwork 122.

[0042] Once the second electronic reply message has been received, the location services client 104 is arranged to carry out the step 508 of processing the second reply message to obtain the datum 300. In view of the fact that the datum 300 is contained (encapsulated) in the second reply message, the step 508 of processing the reply message basically involves extracting the datum 300 from the second reply message.

[0043] As outlined in the preceding paragraph, the location services client 104 is arranged to perform the step 206 of providing the location information system 106 with the electronic location request message. The location information system 106 is arranged to perform various steps, which are contained in the flow chart 600 of fig. 6, in response to being provided with the electronic location request message. The first of these steps 602 involves receiving the location request message via the internetwork 122. To allow the location request message to be sent via the inter-network 122 it is encapsulated in an IP packet. Consequently, the step 602 of receiving the location request message involves extracting the request message from the IP packet.

[0044] Following on from the previous step 602, the location information system 106 carries out the step 504 of processing the datum (which is contained in the location request message) to identify the mobile electronic communication device 118 of interest. More specifically, the location information system 106 examines the second field 304 of the datum 300, which contains data that represents a unique communication session identifier created by the location information system 106. The location information system 106 uses the communication session identifier to * look-up' an internal record

(database) to determine the corresponding mobile electronic communication device 118 to which the datum 300 was assigned.

[0045] Once the location information system 106 has carried out the step 604 of identifying the mobile electronic communication device 118 of interest, it proceeds to perform the step 606 of issuing the location of the mobile electronic communication device 118 of interest (which corresponds to the communication session identifier contained in the second field 304 of the datum) . The step 606 of issuing the location involves passing data, which represents the location of the mobile electronic communication device 118 of interest, to the communication software and hardware of the location information system 106. In this regard, the communication software and hardware encapsulates the data (representing the location) in an IP packet and sends it to the location services client 104 via the inter-network 122.

[0046] The location of the mobile electronic communication device is typically a set of geographical coordinates for the mobile electronic communication device 118 of interest. The location may also include a velocity estimate of the mobile electronic communication device 118 of interest. The present invention assumes that the location has already been calculated. As such, how the location is calculated is beyond the scope of the specification. It is, however, noted that persons skilled in the art will readily appreciated that there are various techniques for calculating the actual location of the mobile electronic communication device 118 of interest . An example of one technique that can be used is the satellite based Global Positioning System for obtaining the latitude and longitude coordinates of the mobile electronic communication devices 122.

[0047] Given that there may be certain privacy related issues surrounding the issuance of the location of the mobile electronic communication devices 118, the location information system 106 is arranged to determine whether it is permissible to issue the location of the mobile electronic communication device 118 of interest. There are various steps involved in determining whether the location can be issued and these steps are contained in the flow chart 700 of fig. 7. In this regard, the first step 702 that the location information system 106 performs is to provide the privacy system 112 with a first electronic authority request message, which identifies the mobile electronic communication device 118 of interest, via the inter-network 122. Given that the authority request message is sent to the privacy system 112 via the inter-network

122, the location information system 106 initially passes the authority request message to its communication software and hardware . The communication software and hardware encapsulates the authority request in an IP packet, which is sent via the inter-network 122.

[0048] On receiving the first electronic authority request message, the privacy system 112 is arranged to process the message to determine whether the location information system 106 has the authority to proceed.

Subsequent to this the privacy system 112 will respond by issuing the location information system 106 with a first reply message, which is sent via the inter-network 122. Consequently, the location information system 106 is arranged to perform the step 704 of receiving the first reply message and subsequently performing the step 706 of processing the first reply message to determine whether it is permissible to obtain the location of the mobile electronic communication device 118 of interest. Given that the first reply message is received via the inter-network 122, the step 706 of processing the first reply message involves extracting the reply message from the IP message.

[0049] If, as a result of the previous step 706, it is permissible to issue the location of the mobile electronic communication device 118 of interest, the location information system 106 proceeds to perform the step 708 of obtaining the location of the mobile electronic communication device 118. At this stage, the location information system 106 carries out the step 710 of providing the privacy system 112 with a second authority message that comprises the location obtained during the previous step 708. The second authority message is sent to the privacy system 112 via the inter-network 122. Thus, the communication software and hardware of the location information system 106 encapsulates the second authority message in an IP packet.

[0050] On receiving the second authority message, the privacy system 112 processes the message to determine whether the location (contained in the second authority message) is permissible to issue. In response to the second authority message, the privacy system 112 issues a second reply message via the inter-network 122. Consequently, the location information system 106 is arranged to perform the step 712 of receiving (via the inter-network 122) the second reply message. After receiving the second reply message the location information system 106 carries out the step 714 of processing the second reply message to determine whether it is permissible to issue the location obtained during the previous step 708. The step 714 of processing the second reply message comprises retrieving the message from an IP packet and extracting the location from the second reply message .

[0051] If, as a result of the previous step 714, it is determined that it is permissible to issue the location the location information system 106 proceeds with the aforementioned step 606 of issuing the location of the mobile electronic communication device 118 of interest. If as a result of earlier steps 706 and 714 it is deemed not to be permissible to issue the location, the location information system 106 will not proceed with the step 606 of issuing the location of the mobile electronic communication device 118 of interest. Instead, the location information system 106 will issue the location services client 104 with an error message indicating that it is not possible to obtain the location.

[0052] As described in the preceding paragraphs of this specification, the location services client 104 can attempt to obtain the datum 300 from the presence information system 108 or the pseudonym processing system 110. In relation to obtaining the datum 300 from the presence information system 108, the location services client 104 is arranged to provide the presence information system 108 with the datum request. The presence information system 108 is arranged to perform several steps in response to being provided with the datum request. In this regard, the steps are shown in the flow chart 800 of fig. 8. The first 802 of these steps involves receiving the datum request message via the inter-network 122. Subsequent to the initial step 802, the presence information system 108 performs the step 804 of processing the datum request to identify the mobile electronic communication device 118 of interest. As indicated previously, the datum request message comprises an identifier (for example, an IP address) of the mobile electronic communication device 118 of interest. Thus, the step 804 of processing the datum request message involves examining the identifier contained therein. Furthermore, because the datum request message is transferred via the inter-network 122 the step 804 of processing the datum request message involves extracting the request message from an IP packet.

[0053] Once the presence information system 108 has identified the electronic communication device 118 of interest, it proceeds with the step 806 of retrieving the datum 300 assigned to the electronic communication device 118 of interest. This involves retrieving the appropriate datum 300 from a database. Subsequent to retrieving the datum 300, the presence information system 108 performs the step 808 of issuing the location services client 104 with the datum 300. The datum 300 is passed to the communication software and hardware of the presence information system 108, which encapsulates the datum 300 in an IP packet and sends the packet via the inter-network 122.

[0054] When the location services client 104 attempts to obtain the datum 300 from the pseudonym processing system 110 it sends the datum request message to the pseudonym processing system 110, as outlined previously. Consequently, the pseudonym processing system 110 is arranged to carry out several steps on being provided with the datum request message. In this regard, the steps are shown in the flow chart 900 of fig. 9. The first step 902 basically involves receiving the datum request message via the inter-network 122. On receiving the datum request message the pseudonym processing system 110 proceeds to perform the step 904 of processing the datum request message to identify a pseudonym for the electronic communication device 118 of interest. As indicated previously, the pseudonym could be in the form of an encrypted identifier of the electronic communication device 118. The step 904 of processing the datum request message also includes retrieving the request message from an IP packet and retrieving the pseudonym from the message .

[0055] The pseudonym processing system 110 is further arranged to perform the step 906 of using the pseudonym to determine a verinym for the electronic communication device 118 of interest. If, for example, the pseudonym was in the form of an encrypted identifier the step 906 of using the pseudonym would comprise decrypting the pseudonym. The decrypted pseudonym represents the verinym. Once the pseudonym processing system 110 has obtained the verinym it carries out the steps 908, 910 and 912 of providing the presence information system 108 with a datum request message that is associated with the verinym, receiving a reply message from the presence information system 108, and processing the reply to obtain the datum 300. These step 908, 910 and 912 are effectively the same as the aforementioned steps 404, 406, and 408 performed by the location services client 104 when requesting the datum from the presence information system 108.

[0056] The last step 914 performed by the pseudonym processing system 110, after obtaining the datum 300 from the presence information system 108, is to send the datum 300 to the location services client 104. The datum 300 is sent via the inter-network 122 and is therefore processed by the communication software and hardware of the pseudonym processing system 110 so that it is encapsulated in an IP packet .

[0057] While the invention has been described with reference to the present embodiment, it will be understood by those skilled in the art that alterations, changes and improvements may be made and equivalents may be substituted for the elements thereof and steps thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt the invention to a particular situation or material to the teachings of the invention without departing from the central scope thereof. Such alterations, changes, modifications and improvements, though not expressly described above, are nevertheless intended and implied to be within the scope and spirit of the invention. Therefore, it is intended that the invention not be limited to the particular embodiment described herein and will include all embodiments falling within the scope of the independent claims .

Claims

What is claimed is:

1. A method of requesting location information, the method comprises the steps of: obtaining a datum that has been assigned to a computing device; processing the datum to identify a location information system which assigned the datum to the computing device; and providing the location information system with a location request, which is associated with the datum, for the location information.

2. The method as claimed in claim 1, wherein the step of obtaining the datum comprises the steps of: identifying a presence information system associated with the computing device; providing the presence information system with a first datum request that is associated with a computing device identifier which is known to the presence information system; receiving a first reply from the presence information system; and processing the first reply to obtain the datum.

3. The method as claimed in claim 2, wherein the step of obtaining the datum comprises the steps of : obtaining a pseudonym associated with the computing device; providing a pseudonym processing system with a second datum request that is associated with the pseudonym; receiving a second reply from the pseudonym processing system; and processing the second reply to obtain the datum.

4. The method as claimed in claim 3 , wherein the steps of providing the location information system with the location request, providing the presence information system with the first datum request, and providing the pseudonym processing system with the second datum request respectively comprise sending the location request, sending the first datum request , and sending the second datum request via a communication system, and wherein the steps of receiving the first reply from the presence information system and receiving the second reply from the pseudonym processing system respectively comprise receiving the first reply, and receiving the second reply via the communication system.

5. The method as claimed in claim 1, wherein the datum comprises a public address of the location information system and a unique identifier created by the location information system for the computing device.

6. The method as claimed in claim 1, wherein the steps are performed by a gateway mobile location centre.

7. A method of responding to a request for location information, the method comprises the steps of: receiving a location request, which is associated with a datum, for the location information; processing the datum to identify a computing device to which a location information system assigned the datum; and issuing a location of the computing device.

8. The method as claimed in claim 7, wherein the step of issuing the location of the computing device comprises the steps of: providing a first authority request to a privacy system that is associated with the computing device; receiving a first reply from the privacy system; processing the first reply to determine whether it is permissible to obtain the location; obtaining the location if, as a result of processing the first reply, it is determined to be permissible; providing a second authority request to the privacy system; receiving a second reply from the privacy system; processing the second reply to determine whether it is permissible to issue the location,- and issuing the location if, as a result of processing the second reply, it is determined to be permissible.

9. The method as claimed in claim 8 , wherein the steps of receiving the location request, receiving the first reply, and receiving the second reply respectively comprise receiving the location request, receiving the first reply, and receiving the second reply via. a communication system, and wherein the steps of issuing the location, providing the first authority request, and providing the second authority request respectively comprise sending the location, sending the first authority request, and sending the second authority request via the communication system.

10. The method as claimed in claim 7, wherein the datum comprises a public address of the location information system and a unique identifier created by the location information system for the computing device.

11. A method of responding to a request for a piece of information for use in requesting location information, the method comprises the steps of: receiving a datum request ; processing the datum request to identify a computing device ,- obtaining a datum that has been assigned to the computing device by a location information system; and issuing the datum.

12. The method as claimed in claim 11, wherein the step of receiving the datum request comprises receiving the datum request via a communication system, and wherein the step of issuing the datum comprises sending the datum via the communication system.

13. The method as claimed in claim 11, wherein the datum comprises a public address of the location information system and a unique identifier created by the location information system for the computing device.

14. A method of responding to a request for a piece of information for use in requesting location information, the method comprises the steps of: receiving a datum request; processing the datum request to identify a pseudonym associated with a computing device; determining a verinym that is associated with the pseudonym; providing a presence information system with a datum request that is associated with the verinym; receiving a reply from the presence information systeleprocessing the reply to obtain a datum that has been assigned to the computing device by a location information system; and issuing the datum.

15. The method as claimed in claim 14, wherein the steps of receiving the datum request and receiving the reply respectively comprise receiving the datum request and receiving the reply via a communication system, and wherein the steps of providing the presence information system with the datum request and issuing the datum respectively comprise sending the datum request and issuing the datum via the communication system.

16. The method as claimed in claim 14, wherein the datum comprises a public address of the location information system and a unique identifier created by the location information system for the computing device.

17. A device for requesting location information, the device comprises a processing means arranged to: obtain a datum that has been assigned to a computing device ; process the datum to identify a location information system which assigned the datum to the computing device; and provide the location information system with a location request, which is associated with the datum, for the location information.

18. The device as claimed in claim 17, wherein the processing means is arranged to obtain the datum by: identifying a presence information system associated with the computing device; providing the presence information system with a first datum request that is associated with a computing device identifier which is known to the presence information system; receiving a first reply from the datum issuing system; and processing the first reply to obtain the datum.

19. The device as claimed in claim 17, wherein the processing means is arranged to obtain the datum by. obtaining a pseudonym associated with the computing device; providing a pseudonym processing system with a second datum request that is associated with the pseudonym; receiving a second reply from the pseudonym processing system; and processing the second reply to obtain the datum.

20. The device as claimed in claim 19, wherein the processing means is arranged to provide the location information system with the location request, provide the presence information system with the first datum request, and provide the pseudonym processing system with the second datum request by respectively sending the location request, sending the first datum request , and sending the second datum request via a communication system, and wherein the processing means is arranged to receive the first reply from the datum issuing system and receive the second reply from the pseudonym processing system by respectively receiving the first reply, and receiving the second reply . via the communication system.

21. The device as claimed in claim 17, wherein the datum comprises a public address of the location information system and a unique identifier created by the location information system for the computing device.

22. The device as claimed in claim 17, wherein the device is in the form of a gateway mobile location centre.

23. A device for responding to a request for location information, the device comprising a processing means is arranged to: receive a location request, which is associated with a datum, for the location information; process the datum to identify a computing device to which a location information system assigned the datum; and issue a location of the computing device.

24. The device as claimed in claim.23, wherein the processing means is arranged to issue the location of the computing device by: providing a first authority request to a privacy system that is associated with the computing device; receiving a first reply from the privacy system; processing the first reply to determine whether it is permissible to obtain the location; obtaining the location if, as a result of processing the first reply, it is determined to be permissible; providing a second authority request to the privacy system; receiving a second reply from the privacy system,- processing the second reply to determine whether it is permissible to issue the location; and issuing the location if, as a result of processing the second reply, it is determined to be permissible.

25. The device as claimed in claim 24, wherein the processing means is arranged to receive the location request, receive the first reply, and receive the second reply by respectively receiving the location request, receiving the first reply, and receiving the second reply via a communication system, and wherein the processing means is arranged issue the location, provide the first authority request, and provide the second authority request by respectively sending the location, sending the first authority request, and sending the second authority request via the communication system.

26. The device as claimed in claim 23, wherein the datum comprises a public address of the location information system and a unique identifier created by the location information system for the computing device.

27. A device for responding to a request for a piece of information for use in requesting location information, the device comprises a processing means arranged to : receive a datum request; process the datum request to identify a computing device ; obtain a datum that has been assigned to the computing device by a location information system; and issue the datum.

28. The device as claimed in claim 27, wherein the processing means is arranged to receive the datum request by receiving the datum request via a communication system, and wherein the processing means is arranged to issue the datum by sending the datum via the communication system.

29. The device as claimed in claim 27, wherein the datum comprises a public address of the location information system and a unique identifier created by the location information system for the computing device.

30. A device for responding to a request for a piece of information for use in requesting location information, the device comprises a processing means arranged to : receive a datum request; process the datum request to identify a pseudonym associated with a computing device,- determine a verinym that is associated with the pseudonym; provide a presence information system with a datum request that is associated with the verinym; receive a reply from the presence information system,- process the reply to obtain a datum that has been assigned to the computing device by a location information system; and issue the datum.

31. The device as claimed in claim 30, wherein the processing means is arranged to receive the datum request and receive the reply by respectively receiving the datum request and receiving the reply via a communication system, and wherein the processing means is arranged to provide the presence information system with the datum- request and issue the datum by respectively sending the datum request and issuing the datum via the communication system.

32. The device as claimed in claim 30, wherein the datum comprises a public address of the location information system and a unique identifier created by the location information system for the computing device.

33. A computer program comprising at least one instruction for causing a computing device to carry out the method as claimed in claim 1.

34. A computer program comprising at least one instruction for causing a computing device to carry out the method as claimed in claim 7.

35. A computer program comprising at least one instruction for causing a computing device to carry out the method as claimed in claim 11.

36. A computer program comprising at least one instruction for causing a computing device to carry out the method as claimed in claim 14.

37. A computer readable medium comprising the computer program claimed in claim 33.

38. A computer readable medium comprising the computer program claimed in claim 34.

39. A computer readable medium comprising the computer program claimed in claim 35.

40. A computer readable medium comprising the computer program claimed in claim 36.