U.S. patent application number 11/814333 was filed with the patent office on 2008-05-08 for method and apparatus for handling emergency calls.
Invention is credited to Ake Busin, Magnus Olsson, Stephen Terrill.
Application Number | 20080107243 11/814333 |
Document ID | / |
Family ID | 36000959 |
Filed Date | 2008-05-08 |
United States Patent
Application |
20080107243 |
Kind Code |
A1 |
Terrill; Stephen ; et
al. |
May 8, 2008 |
Method And Apparatus For Handling Emergency Calls
Abstract
A method and apparatus for obtaining location information for
subscribers connected to an IP access network (300), in order to
enable supply of such location information in connection with
emergency calls directed to a multimedia service network (302). A
request is received (3:1) at the multimedia service network from a
subscriber (A) containing an IP address currently assigned to the
subscriber. In response thereto, the multimedia service network
sends a location query (3:2) including said IP address to the IP
access network, which then can retrieve (3:3, 3:4) location
information for the subscriber based on the IP address, by
determining at which point of access in the IP access network the
IP address is currently used. The IP access network then submits
(3:5) the obtained location information to the multimedia service
network in response to the location query.
Inventors: |
Terrill; Stephen; (Madrid,
ES) ; Busin; Ake; (Sollentuna, SE) ; Olsson;
Magnus; (Stockholm, SE) |
Correspondence
Address: |
ERICSSON INC.
6300 LEGACY DRIVE, M/S EVR 1-C-11
PLANO
TX
75024
US
|
Family ID: |
36000959 |
Appl. No.: |
11/814333 |
Filed: |
December 22, 2005 |
PCT Filed: |
December 22, 2005 |
PCT NO: |
PCT/SE05/02016 |
371 Date: |
August 9, 2007 |
Current U.S.
Class: |
379/45 |
Current CPC
Class: |
H04W 64/00 20130101;
H04L 65/4007 20130101; H04W 4/18 20130101; H04W 4/20 20130101; H04L
67/04 20130101; H04L 67/18 20130101; H04W 76/50 20180201; H04W 4/90
20180201; H04L 65/1096 20130101; H04W 4/02 20130101; H04L 65/1016
20130101 |
Class at
Publication: |
379/45 |
International
Class: |
H04M 11/04 20060101
H04M011/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 19, 2005 |
SE |
0500165-6 |
Claims
1. A method, of obtaining location information for a subscriber
currently connected to an IP access network at a certain point of
access, the method executed in a session managing node of a
multimedia service network and comprising the following steps:
receiving a request from said subscriber containing an IP address
currently assigned to the subscriber when connected to said point
of access, sending a location query for the subscriber including
said IP address to the IP access network, and receiving location
information for said point of access of the subscriber in response
to the location query, thereby enabling supply of the received
location information to an emergency centre in connection with an
emergency call from said subscriber.
2. The method according to claim 1, wherein the received request
relates to an emergency call, and the obtained location information
is added to the request before sending it to said emergency
centre.
3. The method according to claim 2, wherein said emergency centre
is selected for the request, based on the obtained location
information.
4. The method according to claim 2, wherein the multimedia service
network is an IMS network using SIP signalling, and said request
relating to an emergency call is a SIP INVITE message.
5. The method according to claim 1, wherein it is determined that
the received request is a registration request, and the obtained
location information is saved for later retrieval in the case of a
subsequent emergency call from said subscriber.
6. The method according to claim 5, wherein the multimedia service
network is an IMS network using SIP signalling, and said
registration request is an SIP REGISTER message.
7. The method according to claim 1, wherein the multimedia service
network is an IMS network, the method being executed in an IMS core
entity such as a P-CSCF node in the IMS network.
8. The method according to claim 1, wherein the location query is
sent to a location retrieval unit in the IP access network.
9. An arrangement in a session managing node of a multimedia
service network, for obtaining location information for a
subscriber currently connected to an IP access network at a certain
point of access, the arrangement comprising: means for receiving a
request from said subscriber containing an IP address currently
assigned to the subscriber when connected to said point of access,
means for sending a location query for the subscriber including
said IP address to the IP access network, and means for receiving
location information for said point of access of the subscriber in
response to the location query, thereby enabling supply of the
received location information to an emergency centre in connection
with an emergency call from said subscriber.
10. The arrangement according to claim 9 further comprising logic
means for determining whether the received request relates to an
emergency call, and means for adding the obtained location
information to the request before sending it to said emergency
centre.
11. The arrangement according to claim 10, wherein the logic means
is configured to select said emergency centre for the request,
based on the obtained location information.
12. The arrangement according to claim 10, wherein the multimedia
service network is an IMS network using SIP signalling, and said
request relating to an emergency call is an SIP INVITE message.
13. The arrangement according to claim 9, further comprising logic
means for determining whether the received request is a
registration request, and means for storing the obtained location
information for later retrieval in the case of a subsequent
emergency call from said subscriber.
14. The arrangement according to claim 13, wherein the multimedia
service network is an IMS network using SIP signalling, and said
registration request is a SIP REGISTER message.
15. The arrangement according to claim 9, wherein the multimedia
service network is an IMS network, the arrangement being
implemented in an IMS core entity such as a P-C3CF node in the IMS
network.
16. The arrangement according to claim 9, wherein said sending
means is configured to send the location query to a location
retrieval unit in the IP access network.
17. A method, executed in an IP access network. of providing
location information to a session managing node of a multimedia
service network for a subscriber currently connected to said IP
access network at a certain point of access, the method comprising
the following steps: receiving a location query for said subscriber
containing an IP address currently assigned to the subscriber when
connected to said point of access, retrieving location information
for said point of access of the subscriber based on said IP
address, and providing the retrieved location information for the
subscriber to said session managing node in response to the
received location query.
18. The method according to claim 17, wherein a location retrieval
unit in the IP access network retrieves a point of access identity,
currently associated with the received IP address, from an IP
address administrator in the IP access network.
19. The method according to claim 18, wherein the location
retrieval unit further retrieves said location information based on
the retrieved point of access identity, from a location database in
the IP access network.
20. The method according to claim 10, wherein said location
information is given together with the retrieved point of access
identity.
21. The method according to claim 18, wherein the point of access
identity is a layer 2 address, such as an Ethernet MAC address, ATM
VPI/VCI or other relevant network address, depending on the network
configuration.
22. The method according to claim 17, wherein the multimedia
service network is an IMS network and the retrieved location
information is provided to an IMS core entity such as a P-CSCF node
in the IMS network.
23. A location retrieval unit in an IP access network for providing
location information to a session managing node of a multimedia
service network for a subscriber currently connected to said IP
access network at a certain point of access, the location retrieval
unit comprising: means for receiving a location query for said
subscriber containing an IP address assigned to the subscriber when
connected to said point of access, means for retrieving location
information for said point of access of the subscriber based on
said IP address, and means for providing the retrieved location
information for the subscriber to said session managing node in
response to the received location query.
24. The location retrieval unit according to claim 23, wherein the
retrieving means is configured to retrieve a point of access
identity currently associated with the received IP address, from an
IP address administrator in the IP access network.
25. The location retrieval unit according to claim 24, wherein the
retrieving means is further configured to retrieve said location
information, based on the retrieved point of access identity, from
a location database in the IP access network.
26. The location retrieval unit according to claim 24, wherein the
retrieving means is further configured to obtain said location
information together with the retrieved point of access
identity.
27. The location retrieval unit according to claim 24, wherein the
point of access identity is a layer address, such as an Ethernet
MAC address, ATM VPI/VCI or other relevant network address,
depending on the network configuration.
28. The location retrieval unit according to claim 23, wherein the
multimedia service network is an IMS network and the providing
means is configured to provide the retrieved location information
to an IMS core entity such as a P-CSCF node in the IMS network.
Description
TECHNICAL FIELD
[0001] The present invention relates generally to a method and
apparatus for handling emergency calls in a multimedia service
network. In particular, the invention is concerned with obtaining
required location information for a calling subscriber.
BACKGROUND
[0002] In traditional circuit-switched telephony systems, emergency
services are available for subscribers in situations of emergency,
such as accidents and diseases. Emergency calls are typically first
routed to an emergency centre which then connects the calls further
to relevant emergency service stations, depending on the current
situation, e.g. a hospital, a fire station or the police.
[0003] Details and requirements of emergency services are subject
to regulations prevailing in different countries and regions.
Typically, it is required that the telephony system can provide
relevant location information in order to certify the location of
the calling party. Firstly, it may be important to connect an
incoming call to an emergency centre or service station being
reasonably close to the caller. Secondly, the caller may not for
some reason be able to provide crucial information regarding
his/her whereabouts to the emergency centre, at least not
immediately.
[0004] FIG. 1 illustrates a fixed subscriber terminal A connected
to a telephony network 100 by means of a local exchange LE 102. An
emergency centre 104 is also connected to the network 100, to which
an emergency call is directed from subscriber A. Network 100
further comprises a location database 106 holding geographic
location information on subscribers connected to the network 100,
including subscriber A, e.g. in the form of local street addresses
or the like.
[0005] It is typically required in fixed public networks that local
exchanges therein ensures that a "calling party identifier" is
included in emergency calls when routed to an emergency centre. In
the present example, local exchange 102 has knowledge of subscriber
terminal A being connected to a specific input line in the
exchange, which is associated with a specific calling party
identifier of subscriber terminal A. The local exchange 102 is thus
required to supply the calling party identifier of subscriber
terminal A when transmitting the emergency call to emergency centre
104. In location database 106, the geographic location of
subscriber terminal A is stored together with its calling party
identifier, such that the emergency centre 104 can retrieve that
location information from the location database 106 by means of the
calling party identifier received with the emergency call.
[0006] In a cellular network, a serving Mobile Switching Centre MSC
can include location information in emergency calls from mobile
terminals, such as a cell identification or even more accurate
information in the form of geographic coordinates or the like based
on location services employed in the network. Further, the
receiving emergency centre may also use specific location services
to determine the location of the calling party, if necessary.
[0007] Although the examples above are relevant for traditional
circuit-switched telephone networks, various communication networks
and terminals are used today that are capable of packet-based
multimedia communication using IP (Internet Protocol), including
fixed or mobile computers and telephones. Multimedia services
typically entail IP based transmission of encoded data representing
media in different formats and combinations, including audio,
video, images, text, documents, animations, etc.
[0008] The location of a subscriber terminal is not permanent in
the same way as before, since an IP terminal can be connected to
multimedia service networks more or less regardless of its current
geographic location, while still using the same subscriber
identity. This is evidently the case for mobile terminals, but also
for fixed portable terminals that can be jacked into different
access points at different locations in an IP access network, e.g.
for accessing various "broadband" services.
[0009] A network architecture called "IP Multimedia Subsystem"
(IMS) has been developed by the 3rd Generation Partnership Project
(3GPP) as an open standard for handling multimedia services and
communication sessions in the packet domain. IMS networks can also
be used to provide emergency services, although it is not evident
how to provide relevant location information when required, due to
the roaming possibilities for IP terminals, and this issue has not
yet been solved. IMS is a platform for enabling services based on
IP transport more or less independent of the access technology
used, and will be briefly outlined here.
[0010] The IMS network is thus used for generally controlling
multimedia sessions, and a specification called "SIP" (Session
Initiation Protocol, according to the standard IETF RFC 3261) is
used for handling multimedia sessions in IMS networks. SIP is an
application-layer protocol used by IMS networks and terminals to
establish and control IP based multimedia communications. When
sending SIP messages, an addressing element called "SIP URI"
(Uniform Resource Identifier) is used, such that one SIP URI
indicates the source and another one indicates the destination in
each message.
[0011] FIG. 2 is an exemplary schematic illustration of a basic
scenario when multimedia services are provided for a terminal A by
means of an IMS service network. Terminal A is connected to an IP
access network 200 and communicates media with a remote party B,
such as another terminal or server, in a communication session S.
An IMS network 202A is connected to the IP access network 200 and
handles the session with respect to terminal A, where networks 200
and 202 are typically owned by the same operator. Moreover, if a
terminal is connected to a visited access network, multimedia
services are handled by the terminal's "home" IMS network, i.e.
where it is registered as a subscriber. The remote party B may be
connected to another corresponding IMS network 202B.
[0012] The illustrated session S is basically managed by a node
called S-CSCF (Serving Call Session Control Function) 204 assigned
to terminal A in the IMS network 202A, and the used multimedia
service is enabled and executed by an application server 206
connected to the IMS network 202. Basically, the S-CSCF node 204
serves as a proxy for the application server 206 towards terminal
A, and sends SIP messages coming from terminal A towards the remote
party B, as indicated by a dashed arrow. Further, a main database
element HSS (Home Subscriber Server) 208 stores subscriber and
authentication data as well as service information, among other
things, that the SIP application server 206 can fetch for executing
services for subscribers.
[0013] A node called I-CSCF (Interrogating Call Session Control
Function) 210 in IMS network 202 is connected to other IMS
networks, including network 202B, and acts as a gateway for SIP
messages arriving from such IMS networks. I-CSCF 210 receives SIP
messages concerning the remote party B, as indicated by another
dashed arrow. Another node in IMS network 202 called P-CSCF (Proxy
Call Session Control Function) 212 acts as an entry point towards
the IMS network 204 from any access network, such as IP network
200, and all signalling flows between subscribers of the IMS
network 204 are routed through the P-CSCF 212. Of course, the IMS
network 202 contains numerous other nodes and functions, such as
further S-CSCF nodes and SIP application servers, which are not
shown here for the sake of simplicity.
[0014] As indicated above, it has not been solved how to satisfy
prevailing emergency requirements for providing location
information in emergency calls from IP terminals in a safe and
reliable manner, when an IP based multimedia service network is
used. In particular, it is desirable to supply location information
when an emergency call, coming from an IP terminal that can be
moved between different locations, is routed to an emergency
centre. It is also desirable to select a suitable emergency centre
to which the emergency call is to be routed, depending on the
location of the calling subscriber.
SUMMARY
[0015] The object of the present invention is to address at least
some of the problems outlined above, and to provide a solution for
enabling the supply of location information for a subscriber to an
emergency centre in connection with an emergency call, when
connected to an IP access network. This object and others may be
obtained by providing a method and apparatus according to the
attached independent claims.
[0016] According to one aspect, the present invention provides a
method, executed in a multimedia service network, of obtaining
location information for subscribers connected to an IP access
network. When a request is received from a subscriber containing an
IP address currently assigned to the subscriber, a location query
including said IP address is sent to the IP access network.
Location information for the subscriber is then received therefrom
in response to the location query, thereby enabling supply of the
received location information in connection with an emergency call
from said subscriber.
[0017] If it is determined that the received request relates to an
emergency call, the obtained location information is added to the
request before sending it to an emergency centre. The emergency
centre may be selected for the request based on the obtained
location information. The multimedia service network may be an IMS
network using SIP signalling, and the request relating to an
emergency call is then typically an SIP INVITE message.
[0018] On the other hand, if it is determined that the received
request is a registration request, the obtained location
information may be saved for later retrieval in the case of a
subsequent emergency call from the subscriber. If the multimedia
service network is an IMS network using SIP signalling, the
registration request is typically an SIP REGISTER message.
[0019] When the multimedia service network is an IMS network, the
method can be executed in an IMS core entity such as a P-CSCF node
in the IMS network. The location query above may be sent to a
location retrieval unit in the IP access network, which may also be
referred to as a Location Query Function.
[0020] According to another aspect, the present invention provides
an arrangement in a multimedia service network, for obtaining
location information for subscribers connected to an IP access
network. The inventive arrangement comprises means for receiving a
request from a subscriber containing an IP address currently
assigned to the subscriber, means for sending a location query
including said IP address to the IP access network, and means for
receiving location information for the subscriber in response to
the location query. Thereby, the received location information can
be supplied in connection with an emergency call from said
subscriber.
[0021] The multimedia service network arrangement may further
comprise logic means for determining whether the received request
relates to an emergency call, and means for adding the obtained
location information to the request before sending it to an
emergency centre. The logic means may be configured to select the
emergency centre for the request based on the obtained location
information. If the multimedia service network is an IMS network
using SIP signalling, the request relating to an emergency call may
be an SIP INVITE message.
[0022] The multimedia service network arrangement may further
comprise logic means for determining whether the received request
is a registration request, and means for storing the obtained
location information for later retrieval in the case of a
subsequent emergency call from the subscriber. If the multimedia
service network is an IMS network using SIP signalling, the
registration request is typically an SIP REGISTER message.
[0023] When the multimedia service network is an IMS network, the
arrangement can be implemented in an IMS core entity such as a
P-CSCF node in the IMS network. The sending means may be configured
to send the location query to a location retrieval unit in the IP
access network, which may also be referred to as a Location Query
Function.
[0024] According to yet another aspect, the present invention
provides a method, executed in an IP access network, of providing
location information to a multimedia service network for
subscribers connected to said IP access network. When a location
query is received for a subscriber containing an IP address
currently assigned to the subscriber, location information for the
subscriber is retrieved based on said IP address, and the retrieved
location information for the subscriber is provided to said
multimedia service network in response to the received location
query.
[0025] A location retrieval unit in the IP access network, which
may also be referred to as a Location Query Function, may retrieve
a point of access identity currently associated with the received
IP address, from an IP address administrator in the IP access
network. The location retrieval unit may further retrieve the
location information based on the retrieved point of access
identity, from a location database in the IP access network. The
location information may be given together with the retrieved point
of access identity. The point of access identity may be a layer 2
address, such as an Ethernet MAC address, ATM VPI/VCI or other
relevant network address, depending on the network configuration.
If the multimedia service network is an IMS network, the retrieved
location information may be provided to an IMS core entity such as
a P-CSCF node in the IMS network.
[0026] According to yet another aspect, the present invention
provides a location retrieval unit in an IP access network, which
may also be referred to as a Location Query Function, for providing
location information to a multimedia service network for
subscribers connected to the IP access network. The inventive
location retrieval unit comprises means for receiving a location
query for the subscriber containing an IP address assigned to the
subscriber, means for retrieving location information for the
subscriber based on said IP address, and means for providing the
retrieved location information for the subscriber to the multimedia
service network in response to the received location query.
[0027] The retrieving means may be configured to retrieve a point
of access identity currently associated with the received IP
address, from an IP address administrator in the IP access network.
The retrieving means may be further configured to retrieve the
location information based on the retrieved point of access
identity, from a location database in the IP access network. The
retrieving means may be further configured to obtain said location
information together with the retrieved point of access
identity.
[0028] The point of access identity may be a layer 2 address, such
as an Ethernet MAC address, ATM VPI/VCI or other relevant network
address, depending on the network configuration. If the multimedia
service network is an IMS network, the providing means may be
configured to provide the retrieved location information to an IMS
core entity such as a P-CSCF node in the IMS network.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] The present invention will now be described in more detail
and with reference to the accompanying drawings, in which:
[0030] FIG. 1 is a schematic block diagram of a communication
network providing location information for an emergency call,
according to the prior art.
[0031] FIG. 2 is a schematic block diagram including an IMS
network, in which the present invention can be used.
[0032] FIG. 3 is a block diagram of an IP access network and a
multimedia service network, illustrating a procedure for obtaining
location information, according to one embodiment.
[0033] FIG. 4 is a flow chart illustrating a procedure for
obtaining location information, according to another
embodiment.
[0034] FIG. 5 is a flow chart illustrating a procedure for
providing location information, according to yet another
embodiment.
[0035] FIG. 6 is a block diagram of an IMS core entity in a
multimedia service network, according to yet another
embodiment.
[0036] FIG. 7 is a block diagram of a location retrieval unit in an
IP access network, according to yet another embodiment.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0037] The present invention provides a solution for obtaining
location information for a subscriber connected to an IP access
network, in order to enable supply of the location information to
an emergency centre in connection with an emergency call from said
subscriber. Different embodiments of this solution will now be
described, initially with reference to FIG. 3.
[0038] A subscriber A, operating a fixed terminal capable of IP
communication, is connected to an IP access network 300 at a
certain point of access. Access network 300 is further connected to
a multimedia service network 302, in this case an IMS network like
the one described above for FIG. 2, in which only an IMS core 304
is illustrated here. Here, the IMS core 304 is an entity basically
representing a session managing node used for handling messages
from subscriber A, preferably a P-CSCF node. The IP access network
300 may be configured for so-called fixed broadband access
typically used for multimedia services, although the present
invention is generally not limited in this respect.
[0039] Hence, subscriber A has access to multimedia services
offered by means of multimedia network 302, such as various
emergency services. The IP access network 300 comprises a location
retrieval unit 306, an IP address administrator 308 and a location
database 310, where the latter two nodes or similar may typically
occur in any IP access network. The location retrieval unit 306 is
also sometimes referred to as a "Location query function". The IP
address administrator 308 assigns IP addresses to subscriber
terminals for a limited time period upon request, e.g. when
powered-on, and has knowledge of at which point of access in the
network an IP address is currently used.
[0040] Each point of access in the network 300 may be identified by
means of a layer 2 address such as an Ethernet MAC (Medium Access
Control) address, ATM VPI/VCI (Asynchronous Transfer Mode, Virtual
Path Identifier/Virtual Channel Identifier) or other relevant
network address, depending on the network configuration. The
location database 310 stores information on the physical location
for each point of access in the network 300, such as a street
address, geographic coordinates or the like.
[0041] As mentioned above, it is generally possible for subscribers
to connect at different points of access in the IP access network
300, and it is therefore naturally not evident at which physical
location the subscriber A is currently connected. For example, the
subscriber may basically bring his/her IP communication terminal to
any point of access in the network, e.g. to public sites such as
hotels and airports, or to more private quarters. In addition, a
subscriber may have different IP addresses at different occasions,
which is administrated by the IP address administrator 308.
[0042] A first step 3:1 in the figure illustrates that the IMS core
304 in network 300 receives a multimedia request from subscriber A,
being at a location unknown so far. According to prevailing
standards, the request contains an IP address currently assigned to
the subscriber, and the request may be a session invitation such as
an SIP INVITE message. Since the present solution is concerned with
emergency calls, the received request may primarily be a session
invitation for an emergency call that should be routed to a
suitable emergency centre. However, the request may alternatively
be a regular registration request that is typically sent to a
multimedia service network after an IP terminal has been
powered-on, without requesting a session. In IMS systems where SIP
signalling is used, this would typically be a message called SIP
REGISTER.
[0043] It is assumed here that location information on the calling
party is required in emergency calls, which should be supplied to
the emergency centre together with incoming emergency requests, as
explained in the background section. Thus, in the case of an
emergency request in step 3:1, the IMS network 302 is obliged to
retrieve and add such location information to the request when
transmitting it further to the emergency centre. In the case of a
registration request, however, the IMS network 302 may retrieve and
store the location information in order to supply it at a later
occasion, if a subsequent emergency request should arise from the
same subscriber. However, it should be noted that for some access
networks the latter case is mainly relevant if mobility is not
permitted or possible or expected, so that the subscriber's
location (most likely) remains the same throughout a session.
Otherwise, the emergency centre may request for updated location
information, which however lies outside the scope of the present
invention.
[0044] In a next step 3:2, IMS core 304 sends a location query
including the IP address received in the request, to the location
retrieval unit 306 in network 300, effectively asking for the
location of the subscriber currently using the given IP address. In
response thereto, unit 306 retrieves the identity of the point of
access at which the subscriber currently using the IP address is
connected, from the IP address administrator 308, in a step 3:3.
Unit 306 may receive the point of access identity as a layer 2
address or other network address, depending on the network
configuration, as mentioned above.
[0045] Having obtained the point of access identity, unit 306 can
now retrieve the physical location for that point of access
identity from location database 310, e.g. as a street address or
similar or geographical coordinates, in a further step 3:4.
Alternatively, the physical location may already be given from the
IP address administrator in step 3:3, thereby making step 3:4
superfluous. In either case, the location retrieval unit 306 is now
able to respond to the location query of step 3:2 by providing the
obtained location information to IMS core 304, in a following step
3:5.
[0046] Thereby, IMS core 304 is able to add the received location
information to the request of step 3:1 from subscriber A, if
required, and send it further to an emergency centre as indicated
by a final optional step 3:6. Alternatively, if the request of step
3:1 was a registration request and not an emergency request, IMS
core 304 may just store the location information for later use in
the case of an emergency request from subscriber A, as mentioned
above, naturally without adding it to the registration request.
[0047] The above described solution makes it possible to obtain and
supply required location information in connection with emergency
calls over a multimedia service network coming from subscribers
connected to an IP access network.
[0048] A procedure for obtaining location information for a
subscriber connected to an IP access network, according to one
aspect of the present invention, will now be described with
reference to the flow chart in FIG. 4. The steps in the flow chart
are defined for execution in a multimedia service network,
particularly in an IMS core entity such as a P-CSCF node.
[0049] In a first step 400, a multimedia request is initially
received from the subscriber containing an IP address currently
assigned to the subscriber. In response thereto, a location query
for the received IP address is sent in a next step 402 to the IP
access network, preferably to a location retrieval unit or similar
therein, like the unit 306 shown in FIG. 3. After proceedings in
the IP access network that will be outlined in more detail below,
relevant location information is received therefrom, in following
step 404.
[0050] Next, it is determined in a step 406 whether the received
request relates to an emergency call, i.e. directed to an emergency
service that is requested in a session invitation for an emergency
call from the subscriber. If so, the location information received
in step 404 is added to the emergency call request in a further
step 408 before sending the request to an emergency centre. It
should be noted that the obtained location information may be used
for selecting a suitable emergency centre, e.g. located in the same
region as the subscriber's current location. If it is determined in
step 406 that the received request is not related to an emergency
call, such as in the case of a registration request, the obtained
location information is stored in a final illustrated step 410 for
later use if the subscriber should make an emergency call, instead
of adding it to the request received in step 400.
[0051] Alternatively, this procedure may be simplified by executing
the determination step 406 directly after the first step 400 of
receiving the request. Then, only if the request is related to an
emergency call, the location information may be obtained and
supplied by executing steps 402, 404 and 408, and the storing step
410 may be omitted. In this alternative, no further steps are taken
for location retrieval if the request is not related to an
emergency call.
[0052] A procedure according to another aspect of the present
invention, for providing location information to a multimedia
service network for a subscriber connected to an IP access network,
will now be described with reference to the flow chart in FIG. 5.
The steps in the flow chart are defined for execution in the IP
access network, particularly in a location retrieval unit or the
like implemented therein, sometimes also referred to as a "Location
Query Function". As in the previous examples, the multimedia
service network may be an IMS network and its point of
communication in the procedure below would then be an IMS core
entity such as a P-CSCF node.
[0053] In a first step 500, a location query is received from the
multimedia service network for the subscriber, containing an IP
address currently assigned to the subscriber. In response thereto,
a point of access identity (e.g. a layer 2 address) corresponding
to the given IP address is retrieved from an IP address
administrator in a next step 502. Depending on the access
technology used, the required location information may be given at
this point. Thus, it is checked in a next step 504 whether the
location information has been obtained, and if not, the location
information is retrieved from a location database based on the
point of access identity retrieved above (e.g. layer 2 address) in
a following step 506.
[0054] Eventually, the location information can be provided to the
multimedia service network in a final step 508. On the other hand,
if it was determined in step 504 above that the required location
information has already been obtained, step 508 can be executed
immediately after step 504, as indicated.
[0055] An arrangement in an IMS core entity in a multimedia service
network, e.g. a P-CSCF node, will now be briefly described with
reference to FIG. 6. The IMS core entity 600 is basically adapted
to execute the procedure illustrated in FIG. 4. The IMS core entity
600 comprises first receiving means 602 configured to receive
multimedia requests R from subscribers, and sending means 604
configured to send location queries Q to an IP access network where
said subscribers are connected. IMS core entity 600 further
comprises second receiving means 606 configured to receive location
information L from the IP access network in response to said
queries Q, and adding means 608 configured to add obtained location
information L before sending emergency requests E(L) to an
emergency centre.
[0056] The IMS core entity 600 may further comprise a logic means
610 for controlling the operation of the different means 602-608,
and optionally also for selecting a suitable emergency centre for
the emergency requests E(L), based on obtained location
information. The logic means 610 may also be configured to
recognise whether an incoming multimedia request is directed to an
emergency service, and to determine if location information is to
be added to the request or not. Finally, IMS core entity 600 may
also comprise storing means 612 configured to store received
location information L for later retrieval in the case of
subsequent emergency requests.
[0057] An arrangement in an IP access network for providing
location information to a multimedia service network for a
subscriber connected to the IP access network, will now be briefly
described with reference to FIG. 7. In this example, the
arrangement is implemented in a location retrieval unit 700,
similar to the unit 306 in FIG. 3, basically adapted to execute the
procedure illustrated in FIG. 5.
[0058] The location retrieval unit 700 comprises receiving means
702 configured to receive location queries Q from a multimedia
service network, each query containing an IP address assigned to a
subscriber. Unit 700 further comprises retrieving means 704
configured to retrieve location information L based on said IP
addresses, from an IP address administrator and optionally a
location database in the IP access network. Unit 700 further
comprises providing means 706 configured to provide retrieved
location information L for subscribers to the multimedia service
network in response to received location queries Q.
[0059] It should be noted that FIGS. 6 and 7 illustrate logically
the basic functional elements of the IMS core entity 600 and the
location retrieval unit 700, respectively. However, the skilled
person is free to put them into practice in any suitable manner not
limited to the shown dispositions.
[0060] The present invention, as described with reference to
different embodiments above, offers a simple yet reliable mechanism
for obtaining required location information and for providing it to
an emergency centre, in response to emergency requests from
subscribers connected to an IP access network and requesting
emergency services from a multimedia service network.
[0061] While the invention has been described with reference to
specific exemplary embodiments, the description is in general only
intended to illustrate the inventive concept and should not be
taken as limiting the scope of the invention. For example, the SIP
signalling protocol and IMS concept have been used throughout when
describing the above embodiments, although any other standards and
service networks for enabling multimedia communication may
basically be used. Further, the invention is not limited to any
particular emergency services but may be used for providing
location information to any type of emergency request. The present
invention is defined by the appended claims.
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