WO2010004659A1

WO2010004659A1 - Multimedia gateway and control method thereof

Info

Publication number: WO2010004659A1
Application number: PCT/JP2008/062981
Authority: WO
Inventors: Johan Hjelm; Takeshi Matsumura; Shingo Murakami; Toshikane Oda
Original assignee: Telefonaktiebolaget LM Ericsson AB
Current assignee: Telefonaktiebolaget LM Ericsson AB
Priority date: 2008-07-11
Filing date: 2008-07-11
Publication date: 2010-01-14
Anticipated expiration: 2011-01-11

Abstract

There is provided a multimedia gateway that comprises: an establishing unit that establishes a session with a registration server, an assigning unit that assigns a user identity to a client terminal, a registering unit that registers the user identity with the registration server via the session, a content information receiving unit that receives, from a content server, content information that indicates content maintained by the content server, by forwarding a content information request from the client terminal to the content server, a retrieving unit that retrieves user profile that is associated with the user identity from a profile server, a generating unit that generates personalized content information from the content information based on the user profile, and a providing unit that provides the client with the personalized content information.

Description

DESCRIPTION MULTIMEDIA GATEWAY AND CONTROL METHOD THEREOF

TECHNICAL FIELD

[0001] The present invention generally relates to a multimedia gateway and a method for controlling the multimedia gateway. The present invention particularly relates, but is not limited to, a technology that enables a client terminal to receive personalized service without logging in the service.

BACKGROUND ART ^{' " ■ ■ ■ ' • ■ •} . .

[0002] It is a known art providing a user^" with personalized service. For example, a content server

(e.g., a kind of a Hyper Text Transfer Protocol (HTTP) server) , which serves the user, maintains information about the user's preference. When the user logs in the content server by providing it with his/her credentials

(e.g., a pare of user identity and a password), the content server identifies the user and provides him/her with personalized service based on his/her preference.

[0003] However, the user sometimes may not want to reveal his/her credentials to the content server. In this case, it is not possible for the user to be provided with the personalized service in the conventional art.

[0004] In the conventional art, for example, US 2003/0236896 and US 2003/0204608 disclose a method which provides authentication for data services for at least one user device, using a common-to-multiple- protocol authentication information, based on information stored in a proxy server of a home network, for user device of multiple protocols. However, personalization is not considered in these documents. Moreover, user credentials are revealed to the content server according to these documents.

SUMMARY

[0005] The present invention is intended^' to- . address the above-described problem, and it is a feature thereof to introduce a new technology that enables a user to be provided with a personalized service without revealing his/her credentials to respective service providers.

[0006] According to a first aspect of the present invention, there is provided a multimedia gateway which can communicate with a registration server that accepts registration of a user identity, a client terminal that is operated by a user, a content server that maintains content, and a profile server that maintains user profile in association with a user identity. The multimedia gateway comprises: an establishing unit that establishes a session with the registration server, an assigning unit that assigns a user identity to the client terminal, a registering unit that registers the user identity with the registration server via the session, a content information receiving unit that receives, from the content server, content information that indicates content maintained by the content server, by forwarding a content information request from the client terminal to the content server, a retrieving unit that retrieves user profile that is associated with the user identity from the profile server, a generating unit that generates personalized content information from the content information based on the user profile, and a providing unit that provides the client with the personalized content information. [0007] According to a second aspect of the present invention there is provided a method for controlling a multimedia gateway which can communicate with a registration server that accepts registration of a user identity, a client terminal that is operated by a user, a content server that maintains content, and a profile server that maintains user profile in association with a user identity. The method comprises: establishing a session with the registration server, assigning a user identity to the client terminal), registering the user identity with the registration server via the session, receiving, from the content server, content information that indicates content maintained by the content server, by forwarding a content information request from the client terminal to the content server, retrieving user profile that is associated with the user identity from the profile server, generating personalized content information from the content information based on the user profile, and providing the client with the personalized content information. [0008] The main advantage of the present invention is as follows. The user can be provided with the personalized service while preventing his/her credentials from being revealed to the respective service providers. In other words, it is not necessary for the user to log in the respective services. [0009] Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.

BRIEF DESCRIPTION OF DRAWINGS

[0010] Fig. 1 shows network architecture according to exemplary embodiments of the present invention; [0011] Fig. 2 is a functional block diagram of the IP Multimedia Subsystem (IMS) gateway (IG) ; [0012] Fig. 3 is a sequence diagram showing a flow of the process by which the HTTP application level gateway (ALG) and the back-to-back user agent (B2BUA) assign an IMS Public User Identity (IMPU) to the client terminal and register the IMPU with the IMS core according to one of the exemplary embodiments; [0013] Fig. 4 is a sequence diagram showing a flow of the process by which the client terminal is provided with the personalized service from the content server via the IG according to one of the exemplary embodiment ;

[0014] Fig. 5 is a sequence diagram showing a flow of the process by which the Universal Plug and Play Control Point (UPnP CP) searches for the rendering devices such as the digital media renderer (DMR) according to an alternative embodiment;

[0015] Fig. 6 is a sequence diagram showing a flow of the process by which the client terminal is provided with the personalized service from the content server via the IG according to the alternative embodiment; [0016] Fig. 7 is a sequence diagram showing a flow of the process by which the client terminal instructs the DMR to render the content according to the alternative embodiment; and

[0017] Fig. 8 is a sequence diagram showing a flow of the process by which the HTTP ALG provide the content server with the session token, and the content server authenticates the HTTP ALG according to still another embodiment . DETAILED DESCRIPTION

[0018] Embodiments of the present invention will now be described with reference to the attached drawings. Each embodiment described below will be helpful in understanding a variety of concepts from the generic to the more specific.

[0019] It should be noted that the technical scope of the present invention is defined by claims, and is not limited by each embodiment described below. In addition, not all combinations of the features described in the embodiments are necessarily required for realizing the present invention.

[0020] The following embodiments are described in the context of IP Multimedia Subsystem (IMS) , but the present invention is not limited thereto. The IMS core described below may instead, for example, be a registration server that manages an association between the user and the user identity. Moreover, instead of an IMS Public User Identity (IMPU), an Open ID (http://www.openid.net/) may be used as user identity. Similar replacement can be applied to any other specific terms such as HTTP, UPnP, and so on. It should be noted that if the present invention is applied for IMS, it is possible to provide the user with a secure authentication and authorization from the IMS, which is advantageous over the conventional art. [0021] Fig. 1 shows network architecture according to exemplary embodiments of the present invention. There are a local network 100, the Internet 110, and an IMS network 120. Since the IMS network is a logical network implemented on the Internet 110, respective nodes in the Internet 110 and the IMS network 120 can communicate with each other as long as they conform to a common protocol.

[0022] The local network 100 comprises a client terminal 101, a digital media renderer (DMR) 102, and an IMS gateway (IG) 103. The client terminal 101 includes an HTTP client, and can communicate with a content server 111 in the Internet 110 via the IG 103. The DMR 102 is a kind of a rendering device, includes an HTTP client and a Universal Plug and Play (UPnP) Renderer, and can communicate with the content server 111 via the IG 103. Alternatively, the DMR 102 may not include the HTTP client, and send a request to the IG 103 using the UPnP technology. The DMR 102 can render the content (e.g., a multimedia stream) received from the content server 111. The IG 103 works as an IMS User Equipment (IMS UE) , and has several functions, which are described with reference to Fig. 2 later. [0023] The content server 111 maintains content. The content server 111 includes an HTTP server, and can provide the IG 103 with the content and content information that indicates the maintained content. [0024] The IMS network 120 comprises an IMS core 121, a profile server 122, and an IMS application server (IMS AS) 123. The IMS core 121 includes a Call Session Control Function (CSCF) , which manages registration of IMPUs from IMS UEs. The profile server 122 maintains user profile in association with the IMPU. The IMS AS 123 may serve the content server 111 in some embodiments.

[0025] Fig. 2 is a functional block diagram of the IG 103. The IG 103 includes a UPnP Control Point (UPnP CP) 201, an HTTP application level gateway (HTTP ALG) 202, a back-to-back user agent (B2BUA) 203, and a database (DB) 204 that is maintained in, for example, static random access memory (RAM) .

[0026] Note that the UPnP CP 201, the HTTP ALG 202, and the B2BUA 203 may be implemented using dedicated hardware, software executed by a processor (not shown) or a combination thereof. For example, they can be implemented as a web application in Tomcat, Java beans or some other similar framework. This implies that they may be implemented as separate software modules. The modules are assumed to communicate with each other using inter-process communication, shared memory (not shown), or the like. [0027] The UPnP CP 201 can search the local network 100 for UPnP-enabled devices such as DMR 102. The UPnP CP 201 stores identifier of the discovered devices in the DB 204. [0028] The HTTP ALG 202 works as an HTTP proxy server between the local network 100 and the Internet 110. The HTTP ALG 202 intercepts messages communicated between the local network 100 and the Internet 110, and modifies the messages as needed (described more in detail later) .

[0029] The B2BUA 203 is IMS-enabled, and obtains an IMS Private User Identity (IMPI) and IMPU (s) from a Universal Integrated Circuit Card (UICC) 205, which is connected to the IG 103. To be more specific, the UICC 205 includes an IMS Subscriber Identity Module (ISIM) 206, which maintains an IMPI and at least one IMPU. The B2BUA 203 communicates with the IMS network 120 using the obtained IMPI and IMPU (s) .

[0030] The HTTP ALG 202, together with the B2BUA 203, assigns one of the IMPUs to the client terminal 101, and the B2BUA 203 registers the assigned IMPU with the IMS core 121 (to be more exact, the CSCF in the IMS core 121) . Although arbitrary scheme can be employed for the assignation of the IMPU, one possible scheme is as follows. A user of the client terminal 101 accesses the HTTP ALG 202 using a Uniform Resource Identifier (URI) of the HTTP ALG 202. Responsive to the access, the HTTP ALG 202 prompts the user to choose one of the IMPUs maintained in the ISIM 206. The user chooses his/her own IMPU and inputs his/her Personal Identification Number (PIN) . If the correct PIN is input, the HTTP ALG 202 decides to assign the chosen

IMPϋ to the client terminal 101.

[0031] Fig. 3 is a sequence diagram showing a flow of the process by which the HTTP ALG 202 and the B2BUA

203 assign an IMPU to the client terminal 101 and register the IMPϋ with the IMS core 121. When the IG

103 is turned on, the process commences.

[0032] In step S301, the B2BUA 203 sets up a session with the IMS core 121. The later communications between the B2BUA 203 and the IMS core

121 are performed via this session. Through the session setup, the B2BUA 203 receives the session token of this session (i.e., identifier of the session) .

[0033] In step S302, the client terminal 101 accesses the HTTP ALG 202 using HTTP GET.

[0034] In step S303, the HTTP ALG 202 requests the

B2BUA 203 for the list of IMPUs maintained in the ISIM

206, and in step S304, the HTTP ALG 202 receives the list.

[0035] In step S305, the HTTP ALG 202 replies to the client terminal 101 with the list received in step

S304.

[0036] In step S306, the client terminal 101 sends an indication of the IMPU chosen by the user, and the corresponding PIN input by the user.

[0037] In step S307, the HTTP ALG 202 passes the indication and the PIN to the B2BUA 203. [0038] In step S308, if the input PIN is valid for the chosen IMPU, the B2BUA 203 registers the IMPU with the IMS core 121 using SIP SUBSCRIBE. Moreover, although not shown, the HTTP ALG 202 stores the association between the IMPU and identifier of the client terminal 101 in the DB 204. [0039] In step S309, the IMS core returns the acknowledgement (a 200 OK message) to the B2BUA 203, and in step S310, the B2BUA 203 informs the HTTP ALG 202 of the acknowledgement.

[0040] In step S311, the HTTP ALG returns a 200 OK message to the client terminal 101.

[0041] Fig. 4 is a sequence diagram showing a flow of the process by which the client terminal 101 is provided with the personalized service from the content server 111 via the IG 103. [0042] The usage of the invention proceeds as follows:

In step S401, the client terminal 101 requests content information that indicates content maintained by the content server 111. The request (content information request) is performed using HTTP GET, which includes identifier of the client terminal 101 (Device ID) . The request is intercepted by the HTTP ALG 202. [0043] In step S402, the HTTP ALG 202 forwards the request to the content server 111. [0044] In step S403, the content server 111 returns the content information to the HTTP ALG 202. [0045] In step S404, the HTTP ALG 202 refers to the DB 204 and identifies the IMPϋ of the client terminal 101 based on the Device ID received in step S401. Then, the HTTP ALG 202 requests the B2BUA 203 for the user profile associated with the IMPU. [0046] In step S405, the B2BUA 203 sends a SIP SUBSCRIBE message with the IMPU to the profile server 122. Responsive to the SIP SUBSCRIBE message, in step S406, the profile server 122 returns the user profile that is associated with the IMPU to the B2BUA 203. [0047] The user profile contains, for example, access control lists, templates, and so on. To be more specific, the user profile may contain a document document-rendering template that is to be used to render the content information received from the content server 111. This template may consist of, for example, XHTML and CSS elements. This template may also contain scripting elements, for example, ECMAScript elements, which can be used to initiate actions .

[0048] In step S407, the B2BUA 203 passes the user profile to the HTTP ALG 202.

[0049] It should be noted that the assignation of an IMPU to the client terminal 101 and the registration of the IMPU to the IMS core 121 has been performed in advance in the present embodiment (see Fig. 3) . However, the assignation and the registration may be performed during the process of Fig. 4 when the client terminal 101 requests the content information for the first time.

[0050] Moreover, the HTTP ALG 202 may cache the user profile in the DB 204 in step S407. In this case, steps S404-S407 can be omitted when the HTTP ALG 202 requests the content information next time. [0051] In step S408, the HTTP ALG 202 generates personalized content information from the content information based on the user profile. One of the examples of the personalization is described below. [0052] It is assumed that the content information is described in the form of the XHTML document, and contains the Electronic Programming Guide (EPG) information. There are embedded metadata information in the XHTML document. This metadata describes the respective content items, for example, in terms of ratings as approved by a ratings agency, according to a standard such as TV-Anytime and the like. The HTTP ALG 202 applies the access control lists of the user profile to the XHTML document, and removes any content items which do not conform to the access control lists. For example, if the access control lists indicate that the user is a child and should not watch movies for adults, the HTTP ALG 202 removes content items for adults from the XHTML document. [0053] Finally, in step S409, the HTTP ALG 202 returns the personalized content information to the client terminal 101.

[0054] In this way, the client terminal 101 can be provided with the personalized service (e.g., personalized content information) from the content server 111 without revealing the user' s credentials to the content server 111.

[0055] The user may choose one of the content items from the personalized content information, and the client terminal 101 may receive the chosen content item from the content server 111 and render it. However, in an alternative embodiment, the client terminal 101 may instruct another device such as DMR 102 to render the chosen content item. This alternative embodiment achieves to separate the rendering device (e.g., the DMR 102) from the controller (e.g., the client terminal 101) . This is advantageous because the user can use the client terminal 101 with sophisticated user interfaces (note that the client terminal 101 may be the personal computer (PC) ) for controlling the content, and can use the DMR 102 with larger screen (note that the DMR 102 may be a TV set) for watching the content. [0056] The alternative embodiment is described with reference to Figs. 5-7.

[0057] Fig. 5 is a sequence diagram showing a flow of the process by which the UPnP CP 201 searches for the rendering devices such as the DMR 102. When the IG 103 is turned on, the process commences. Moreover, the IG 103 may perform the process at a given time interval so that the updated list of the rendering devices can be maintained.

[0058] In steps S501-S506, the UPnP CP 201 performs the standard UPnP discovery procedure. In step S507, the UPnP CP 201 stores identifier of the discovered rendering devices (hereinafter referred to as "device list") in the DB 204, together with their device and service descriptions.

[0059] Fig. 6 is a sequence diagram showing a flow of the process by which the client terminal 101 is provided with the personalized service from the content server 111 via the IG 103. In Fig. 6, steps in which the same operations are performed as Fig. 4 have the same reference numeral as Fig. 4, and there description shall be omitted.

[0060] In step S601, the B2BUA 203 receives the user profile. In this embodiment, the user profile may also contain filtering information for device usage. [0061] In step S602, the B2BUA 203 passes the user profile to the HTTP ALG 202.

[0062] In step S603, the HTTP ALG 202 retrieves the device list from the DB 204.

[0063] In step S604, in addition to the operation described in step S408, the HTTP ALG 202 may incorporate the device list in the personalized content information. In this case, the device list may be filtered based on the filtering information of the user profile .

[0064] Alternatively, the HTTP ALG 202 may not incorporate the device list in the personalized content information, and choose the rendering device when it forwards the instruction to render the content (described later with reference to Fig. 7) . [0065] One of the examples of the filtering is as follows. The user is not allowed to use one of the rendering devices in the local network 100 because, for example, that rendering device is dedicated for another member of family. In this case, the filtering information includes Universally Unique Identifiers (UUIDs) of the rendering devices which are available for the user. The HTTP ALG 202 incorporate the device list of the available devices in the personalized content information.

[0066] Fig. 7 is a sequence diagram showing a flow of the process by which the client terminal 101 instructs the DMR 102 to render the content. [0067] In step S701, through the personalized content information received in step S409 (see Figs. 4 and 6) , the user chooses the content to be rendered. In the case that the personalized content information contains the device list, the user also chooses the device for use in rendering the content. Then, the client terminal 101 sends a request (rendering request) to the HTTP ALG 202. The request includes the identifier (typically, URI) of the content to be rendered, and optionally the identifier of the rendering device.

[0068] In step S702, the HTTP ALG returns a 200 OK message to the client terminal 101. ^'The message may contain a Graphical User Interface (GUI) for use in controlling the rendering (e.g., playout) . [0069] In step S703, in the case that the HTTP GET message received in step S701 does not include the identifier of the rendering device, the HTTP ALG 202 chooses one of the rendering devices discovered in steps S501-S506 (see Fig. 5) based on the user profile. [0070] In the present embodiment, it is assumed that the DMR 102 is specified in the rendering request in step S701, or chosen in step S703.

[0071] In step S704, the HTTP ALG 202 passes the URI of the content and the identifier of the rendering device .

[0072] In step S705, the sends a UPnP action (UPnP SetAVTransportURI) to the DMR 102 using a Simple Object Access Protocol (SOAP) message.

[0073] In step S706, the DMR 102 sends a request (content request) to the HTTP ALG 202. The request is directed to the URI specified in UPnP SetAVTransportURI and intercepted by the HTTP ALG 202. In the case that the DMR 102 does not include the HTTP client, the DMR 102 sends the request to the HTTP ALG 202 via the UPnP CP 201.

[0074] In step S707, the HTTP ALG 202 forwards the request to the content server 111.

[0075] In step S708, the content server returns a 200 OK message, which includes the content to be rendered, to the HTTP ALG 202.

[0076] In steps S709-S710 (optional), the HTTP ALG may inform the B2BUA 203 of the consumption of the content, and the B2BUA 203 may sends a SIP INVITE message, which indicates the content, to the IMS core 121. Responsive to the SIP INVITE message, for example, the IMS core 121 may trigger charging for consumption of the content, and control the Quality of Service (QoS) for the content.

[0077] In step S711, the HTTP ALG relays the content from the content server 111 to the DMR 102. Accordingly, the DMR 102 can obtain and render the content .

[0078] In still another embodiment, the HTTP ALG 202 may send the session token, which was obtained in step S301 (see Fig. 2), to the content server 111 so that the content server 111 can authenticate the session with the HTTP ALG 202. [0079] Fig. 8 is a sequence diagram showing a flow of the process by which the HTTP ALG 202 provide the content server 111 with the session token, and the content server 111 authenticates the HTTP ALG 202. In

Fig. 8, steps in which the same operations are performed as Fig. 4 have the same reference numeral as

Fig. 4, and there description shall be omitted.

[0080] In step S801, the HTTP ALG 202 requests the

B2BUA 203 for the session token, which identifies the session between the B2BUA 203 and the IMS core 121.

[0081] In step S802, the B2BUA 203 returns the

Call ID of the session as the session token.

[0082] In step S803, the HTTP ALG 202 sends an

HTTP GET message to the content server 111 without cookie .

[0083] In step S804, the content server 111 replies to the HTTP ALG 202 with challenge.

[0084] In step S805, the HTTP ALG 202 sends an

HTTP POST message, which includes the Call ID, to the content server 111.

[0085] In step S806, the content server 111 sends the Call ID and the IP address of the HTTP ALG 202 to the IMS AS 123.

[0086] In step S807, the IMS AS 123 passes the

Call ID and the IP address to the IMS core 121.

[0087] In step S808, the IMS core 121 determines whether or not the Call ID is associated with the IP address in the CSCF. If the Call ID is associated with the IP address, the IMS core 121 returns an OK message, which indicates that the HTTP ALG 202 is authenticated, to the IMS AS 123. Otherwise, the IMS core 121 returns an error message to the IMS AS 123 (not shown) . [0088] In step S809, the IMS AS 123 passes the OK message to the content server 111. [0089] In step S810, the content server 111 returns a 200 OK message to the HTTP ALG 202. [0090] In step S811, the ALG 202 sends an HTTP GET message, which includes a response to the challenge, to the content server 111.

[0091] In step S812, the content server 111 returns a 200 OK message, which includes the Call ID as a cookie, to the HTTP ALG 202. The 200 OK message also includes the content information requested from the client terminal 101 in step S401.

[0092] Because the HTTP ALG 202 re-uses the cookie for the subsequent communications, the content server 111 can confirm that the HTTP ALG 202 is authenticated. In other words, instead of the operations in steps S801-S811, the HTTP ALG sends an HTTP GET message with the cookie to the content server 111 after step S401, and the content server 111 returns the 200 OK message in step S812.

[0093] As described above, the present invention is advantageous in that the user can be provided with the personalized service while preventing his/her credentials from being revealed to the respective service providers. In other words, it is not necessary for the user to log in the respective services. Moreover, according to the alternative embodiment, it is possible to separate the rendering device (e.g., the DMR 102) from the controller (e.g., the client terminal 101) . Furthermore, according to still another embodiment, the content server 111 can authenticate the session with the HTTP ALG 202 by use of the session token (e.g., Call ID) that identifies the session between the B2BUA 203 and the IMS core 121. [0094] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A multimedia gateway which can communicate with a registration server that accepts registration of a user identity, a client terminal that is operated by a user, a content server that maintains content, and a profile server that maintains user profile in association with a user identity, comprising: an establishing unit that establishes a session with the registration server; an assigning unit that assigns a user identity to the client terminal; a registering unit that registers the user identity with the registration server via the session; a content information receiving unit that receives, from the content server, content information that indicates content maintained by the content server, by forwarding a content information request from the client terminal to the content server; a retrieving unit that retrieves user profile that is associated with the user identity from the profile server; a generating unit that generates personalized content information from the content information based on the user profile; and a providing unit that provides the client with the personalized content information.

2. The multimedia gateway according to claim 1, further comprising: a searching unit that searches a local network for a rendering device; a storing unit that stores identifier of rendering devices discovered by the searching unit; a rendering request receiving unit that receives a rendering request from the client terminal, the rendering request including identifier of content to be rendered; and an instructing unit that instructs one of the discovered rendering devices to render content identified by the rendering request.

3. The multimedia gateway according to claim 2, wherein the instructing unit chooses the one of the discovered rendering devices based on the user profile.

4. The multimedia gateway according to claim 2, wherein: the personalized content information includes list of the discovered rendering devices, and the instructing unit chooses a rendering device specified in the rendering request as the one of the discovered rendering devices.

5. The multimedia gateway according to any one of claims 2-4, further comprising: a forwarding unit that forwards a content request from the one of the discovered rendering devices, the content request including the identifier of the content to be rendered; and a relaying unit that relays the content to be rendered from the content server to the rendering device .

6. The multimedia gateway according to claim 5, wherein the relaying unit informs the registration server that the content to be rendered was provided for the one of the discovered rendering devices.

7. The multimedia gateway according to any one of claims 1-6, wherein: the establishing unit receives identifier of the session, and the content information receiving unit sends the identifier of the session to the content server.

8. The multimedia gateway according to any one of claims 2-7, wherein: the searching unit performs the search using a Universal Plug and Play (UPnP) protocol, and the instructing unit performs the instruction using at least one of the UPnP protocol and Hyper Text Transfer Protocol (HTTP) .

9. The multimedia gateway according to any one of claims 1-8, wherein: the registration server is a Call Session Control Function (CSCF) of an IP Multimedia Subsystem (IMS), and the user identity is an IMS Public User Identity (IMPU) .

10. A method for controlling a multimedia gateway which can communicate with a registration server that accepts registration of a user identity, a client terminal that is operated by a user, a content server that maintains content, and a profile server that maintains user profile in association with a user identity, comprising: establishing a session with the registration server; assigning a user identity to the client terminal; registering the user identity with the registration server via the session; receiving, from the content server, content information that indicates content maintained by the content server, by forwarding a content information request from the client terminal to the content server; retrieving user profile that is associated with the user identity from the profile server; generating personalized content information from the content information based on the user profile; and providing the client with the personalized content information.

11. The method according to claim 10, further comprising: searching a local network for a rendering device; storing identifier of rendering devices discovered in the step of searching; receiving a rendering request from the client terminal, the rendering request including identifier of content to be rendered; and instructing one of the discovered rendering devices to render content identified by the rendering request .

12. The method according to claim 11, wherein the step of instructing chooses the one of the discovered rendering devices based on the user profile.

13. The method according to claim 11, wherein: the personalized content information includes list of the discovered rendering devices, and the step of instructing chooses a rendering device specified in the rendering request as the one of the discovered rendering devices.

14. The method according to any one of claims 11-13, further comprising: forwarding a content request from the one of the discovered rendering devices, the content request including the identifier of the content to be rendered; and relaying the content to be rendered from the content server to the rendering device.

15. The method according to claim 14, wherein the step of relaying informs the registration server that the content to be rendered was provided for the one of the discovered rendering devices.

16. The method according to any one of claims 10-15, wherein: the step of establishing receives identifier of the session, and the step of receiving the content information sends the identifier of the session to the content server.

17. The method according to any one of claims 11-16, wherein: the step of searching performs the search using a Universal Plug and Play (UPnP) protocol, and the step of instructing performs the instruction using at least one of the UPnP protocol and Hyper Text Transfer Protocol (HTTP) .

18. The method according to any one of claims 10-17, wherein: the registration server is a Call Session Control Function (CSCF) of an IP Multimedia Subsystem (IMS), and the user identity is an IMS Public User Identity (IMPU) .