Title of Invention	BROADCAST/MULTICAST SERVICE SYSTEM AND METHOD PROVIDING INTER-NETWORK ROAMING
Abstract	A method and system for providing a broadcast/multicast (BCAST) service, are provided to guarantee continuity of the BCAST service even when a user roams in the same network or between different networks. The method involves transmitting a BCAST service guide to terminal 300 (S81), receiving a request from the terminal 300 to access at least one BCAST service based on the service guide (S83), transmitting a service authorization request to a BSM unit 120 of a home network 100 (S85), receiving a service authorization response from the BSM unit 120 of the home network 100 (S87) in response to the service authorization request, transmitting to the terminal 300 at least one rights object (RO) to access the at least one BCAST service (S89), and providing the at least one BCAST service to the terminal 300 (S91).

Title of Invention

BROADCAST/MULTICAST SERVICE SYSTEM AND METHOD PROVIDING INTER-NETWORK ROAMING

Abstract

A method and system for providing a broadcast/multicast (BCAST) service, are provided to guarantee continuity of the BCAST service even when a user roams in the same network or between different networks. The method involves transmitting a BCAST service guide to terminal 300 (S81), receiving a request from the terminal 300 to access at least one BCAST service based on the service guide (S83), transmitting a service authorization request to a BSM unit 120 of a home network 100 (S85), receiving a service authorization response from the BSM unit 120 of the home network 100 (S87) in response to the service authorization request, transmitting to the terminal 300 at least one rights object (RO) to access the at least one BCAST service (S89), and providing the at least one BCAST service to the terminal 300 (S91).

Full Text	Technical Field The present invention relates to a mobile communication system and, more par- ticularly, to a broadcast/multicast service system and method supporting inter-network roaming in order to provide a broadcast/multicast service to a user when the user roams in a visiting network which may or may not be a broadcast type network. Background Art A broadcast/multicast service (referred to hereinafter as 'BCAST service') is a new type of service that provides a sky wave broadcast or supplementary information to a mobile terminal. The BCAST service includes both a broadcast service and a multicast service. A broadcast service, offered by a service provider, transmits usable in- formation to' every user who has subscribed to the services of the service provider. A multicast service, also offered by a service provider, transmits information only to a certain group of users who have subscribed for a specific subject or contents. Currently, in the mobile communication network, a simple service is provided to provide simple information to users:, but the BCAST service providing a multimedia type broadcast or various contents to users roaming in the mobile communication network is not provided yet Further, in a situation where the BCAST service is independently operated by each BCAST service provider, if a user who has subscribed to a specific service provider is moved to an area of a different service provider, continuity of the BCAST service for the user is not provided. In addition, when the user who has subscribed for a specific BCAST service with the user's home network roams to a. visiting network, there is no procedure, system or mechanism by which the BCAST service contents of the home network are provided to the user roaming in the visiting network. If the visiting network is a non-broadcast type network or is a broadcast type network which may be the same type as or different from the home network, there is no defined procedure by which the user roaming in the visiting network can obtain the BCAST service of the home network or the BCAST service of the visiting network. This inconveniences the user greatly. Disclosure of Invention Technical Problem Therefore, one object of the present invention is to provide a broadcast/multicast ser vice (BCAST) system and method supporting inter-network roaming, which are capable of guaranteeing continuity of a broadcast/multicast service even when a user roams in the same service network or in a different service network. [7] Another object of the present invention is to provide a broadcast/multicast service system and method supporting inter-network roaming, which are capable of allowing a user who has roamed from a home network to a visiting network to receive a broadcast/multicast service by using a service supported in the visiting network. [8] Still another object of the present invention is to provide a broadcast/multicast service system and method capable of allowing a mobile terminal to use a service provided in a home network when the terminal roams among broadcast type networks. [9] Yet another object of the present invention is to provide a broadcast/multicast service system and method capable of allowing a mobile terminal to use a broadcast/ multicast service through a non-broadcast type network when the terminal roams from a broadcast type network into a non-broadcast type network, [10] Another object of the present invention is to provide a mobile terminal, a system, a method, and computer software embodied on at least one computer-readable medium ....'...- for implementing the method, for providing a BCAST service to an end user/terminal roaming in a visiting network, which overcome limitations and disadvantages associated with the background art. [11] According to an aspect of the present invention, there is provided a method of providing a broadcast/multicast (BCAST) service to a terminal, the method comprising: obtaining, by the terminal, at least one BCAST service from a visiting network when the terminal roams in the visiting network. [12] According to an aspect of the present invention, there is provided a method of obtaining a broadcast/multicast (BCAST) service when a terminal moves from a home network, the method comprising: receiving, by the terminal BCAST service guide in- formation from the visiting network; transmitting, by the terminal, a request to access at least one BCAST service provided in the BCAST service guide information; and obtaining the at least one BCAST service from the visiting network. [13] According to an aspect of the present invention, there is provided a mobile terminal device for obtaining a broadcast/multicast (BCAST) service while roaming in a visiting network, the device comprising: a controller to receive BCAST service guide information from the visiting network, to transmit a request to access at least one BCAST service provided in the BCAST service guide information to the visiting network, and to obtain the at least one BCAST service from the visiting network. [14] According to an aspect of the present invention, there is provided a broadcast/ multicast (BCAST) system comprising: a terminal, a home network of the terminal and configured to communicate with me terminal, and a visiting network configured to communicate with the home network and the terminal, wherein the terminal obtains at least one BCAST service from the visiting network when the terminal roams in the visiting network According to an aspect of the present invention, there is provided a method of providing a broadcast/multicast (BCAST) service when a terminal roams to a visiting network, the method comprising: providing, by a BCAST service distribution/ adaptation (BSDA) unit of the visiting network, a service guide to the terminal; transmittingr by the terminal, a request to access at least one BCAST service to a BCAST subscription management (BSM) unit of the visiting network; transmitting, by the BSM unit of the visiting network, a service authorization request to a BSM unit of a home network of the terminal; receiving, by the BSM of the visiting network, a . service authorization response form the BSM unit of the home network in response to the service authorization request; transmitting, by the BSM unit of the visiting, network, at least one right object for accessing the at least one BCAST service to the terminal; and providing, by the BSD A unit of the visiting network, the at least one BCAST service to the terminal. Additional advantages, obj ects, and features of the invention will be set forth in part in the description which follows and in part will became apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objects and advantages of the invention may be realized and attained as particularly pointed out in the appended claims. Brief Description of the Accompanying Drawings The invention will be described in detail with reference to thefoUowing drawings in which like reference numerals refer to like elements wherein: Figure 1 is a block diagram showing the construction of a BCAST service system according to an embodiment of the present invention; Figure 2 illustrates three examples in which a terminal roams from a home network to a visiting network and receives, a BCAST service in the visiting network according to embodiments of the present invention; Figure 3 is a signal flow chart of a BCAST service method wherein a terminal roams from a home network to a visiting network in accordance with a first embodiment of the present invention; Figure 4 is a signal flow chart, of a BCAST service method wherein a terminal roams from a home network to a visiting network in accordance with a second embodiment of the present invention; Figure 5 is signal flow chart of a BCAST service method wherein a terminal roams from a home network to a visiting network in accordance with a third embodiment of the present invention; and Hgure 6 is signal flow chart of a BCAST service method wherein a terminal roams from a home network to a visiting network in accordance with a fourth embodiment of the present invention. Mode for Invention [24] A broadcast/multicast (BCAST) service system and method that provide inter- network roaming in accordance with preferred embodiments of the present invention will now be described with reference to the accompanying drawings. [25] In the present invention, when a user (having a mobile terminal) who has subscribed to a BCAST service offered by a home network of the terminal roams from the home network to a visiting network, the user can receive, in the visiting network, the same BCAST service that is provided in the home network. In this case, the visiting network may transmit a service guide of the home network to the user in the visiting network, or incorporate the service guide of the home network with the visiting network's service guide and transmits it to the user in the visiting network. [26] In the present invention, when a user who has subscribed to a specific BCAST service roams from the user's home network to a visiting network, the visiting network checks service authentication of the user from the home network and provides a public key (right object) used to view contents of the BCAST service in the visiting network, to the terminal of the user. [27] In the present invention, when a user who has subscribed to a specific BCAST service roams from a broadcast type network to another same broadcast type network, or to a different broadcast type network, or to a non-broadcast type network, the user can still receive the BCAST service through the roamed network. [28] Figure 1 is a block diagram showing the construction of a BCAST service system according to an embodiment of the present invention. All the components of the BCAST service system are operatively coupled. [29] As shown in Figure 1, the BCAST service system includes a contents provider (content creation) 10 for providing contents to distribute in the BCAST service, a broadcast/multicast (BCAST) server 17 for providing a BCAST service to a user or performing protection of the contents or mamtaining/rnanaging the BCAST service, and a terminal 30 for receiving a BCAST service selected by the user from the BCAST server 17. The terminal 30 is a mobile terminal such as a mobile phone, a PDA, etc. and includes known elements including an input unit (e.g., a keypad, buttons, etc.), a controller, a memory, etc. [30] The BCAST service system additionally includes a broadcast distribution system (BDS) 20 or an interaction network (IN) 22 for distributing the BCAST service and performing an interaction function for bi-directional communication, and/or a BDS service distribution (BDS-SD) unit 18 for applying the interaction network according to a bearer. The units 18, 20 and 22 are involved in distributing the BCAST service contents provided by the server 17 to an appropriate device such as the terminal 30 or a home or visiting network. [31] The BDS 20 or the interaction network 22 is a bearer providing a BCAST service such as a DVB-H (Digital Video Broadcasting-Handled), an MBMS (Multimedia Broadcast Multicast Service), a BCMCS (Broadcast Multicast Service), an ISDB-T (Integrated Service Digital Broadcasting-Terrestrial), or a T/S DMB (Terrestrial/Satellite-Digital Multimedia Broadcasting). Thus the BDS 20 and the in- teraction network 22 support the broadcasting mechanism. [32] The BCAST server 17 includes a BCAST service application (BSA) unit 12 for performing functions such as protecting BCAST service contents and/or mamtaining/ managing the BCAST service, a BCAST service distribution/adaptation (BSDA) unit 14 for performing and controlling broadcasting, interface and contents scheduling function by using a specific bearer (DVB-H, MBMS, BCMCS, etc.), and a BCAST subscription management (BSM) unit 16 for performing functions of protecting/ managing service/contents and maintaining/managing user subscription information inorder to manage users who have subscribed to the BCAST service. In this case, the BSA unit 12, the BCAST service distribution/adaptation unit 14 and the BCAST sub- scription/management unit 16 of ths BCAST server 17 transmit or exchange in- formation and signals to each other or with each other through internal communication. Communications from the BSDA unit 14 and the BSM unit 16 may be communicated to a final destination device (e.g., the terminal 30) directly or through one or more of the BDS-SD unit 18, the BDS 20, and the interaction network 22. [33] The terminal 30 includes an application/software for receiving the BCAST service and an application for storing and editing a portion of a BCAST service list provided by the BCAST service provider and storing information on a channel preferred by the user. A BCAST service preference list edited and generated by the user by reflecting the preferences of the user based on the BCAST service list provided; by the service provider is called a wish list. The terminal 30 and its associated network (e.g., the home network) may include an application for managing the wish list, which is called a wish list management application. The terminal 30 can be a mobile phone, a PDA, etc., but is not limited thereto and can be any device that is configured to receive BCAST services. [34] The wish list management application manages the wish list separately, and when a user of a terminal who has subscribed to a service of a specific provider roams to a service area of a different provider and receives a different BCAST service list provided by the corresponding provider, the wish list management application stores and edits a portion of the wish list. When the service provider of the visiting network to which the user has roamed does not provide a service list with respect to the BCAST provided in the terminal's home network, the wish list management application receives the service list from the home network in advance and stores it, or stores a service selected by the user among the provided service list in the wish list in advance. [35] A service provider providing a specific service can transfer a list of services provided in a network of a different service provider with which the service provider has made a roaming contract as well as a list of services provided in its own network. In this case, the service provider should indicate that the service is a service provided by a different provider and not by the service provider itself. Namely, the BCAST server includes a wish list checking application which fetches a wish list of the user's terminal and checks whether the BCAST server can currently provide any service on the wish list, and if the BCAST service cannot provide the services on the wish list, it checks whether a different provider or a different server can provide it. [36] The wish list checking application may exist in every BCAST server, and when a roaming contact exists between service providers, wish list checking applications in the BCAST servers of different providers can interwork so that a service requested by theuser can be provided among BCAST services provided by each BCAST server. It should be noted that 'a wish list of the terminal' and 'a wish list of the user' refer to the same and are used below interchangeably. [37] The BCAST server 17 periodically can check the wish list of the terminal 30 and store it as part of the server 17's stored service broadcast list (server BCAST list) therein or in a separate storage unit outside the BCAST server. The BCAST server 17 can store therein (or in a separate storage unit) information on services which have been provided by different service providers to each requesting user. Thus, when a certain user requests a BCAST service thereafter, the BCAST server 17 searches its storage unit and obtains the current user's history of the BCAST service. And this in- formation can be used by the BCAST server or others to provide the requested BCAST service to the current user more easily and quickly. In addition, even if the user does not provide the user's wish list to the BCAST server, since the BCAST server stores the corresponding information, the BCAST service can be provided to the user. [38] Figure 2 illustrates three different examples in which a terminal may roam and still receive a BCAST service according to the embodiments of the present invention. [39] As shown in Fig. 2, a user of the terminal can roam between the same broadcast type networks (e.g., between MBMSs), can roam between different broadcast type networks (e.g., between the MBMS and the DVB-H), or can roam between a broadcast type network and a non-broadcast type network. In the third example, the broadcast type network is not limited to the MBMS or the DVB-H, but can be the BCMCS, ISDB-T, T/S-DMB, or others, and the non-broadcast type network can be the GSM or CDMA, which does not directly offer the BCAST service or does not support the broadcasting mechanism. [40] In some embodiments of the present invention, when the terminal (user) has subscribed to one or more BCAST services of a home network and roams to another network (visiting network) which may be the same type of broadcast network or a different type of broadcast network the visiting network is configured to provide the BCAST service of the home network to the terminal by obtaining the BCAST service of the home network and broadcasting the BCAST service (contents) to the terminal in the visiting network. In another embodiment, the BCAST service of the visiting network may be provided to the terminal roaming in the visiting network, once the visiting network performs a service authorization check of the terminal through the home network of the terminal. Further, even if the visiting network is a non-broadcast type network, which does not support the broadcasting mechanism, the visiting network can still provide the BCAST service of the home network to the terminal roaming in the visiting network using a unitcast method. For example, even if the visiting network is a non-broadcast type network and only provides a general mobile communication service, the visiting network can still provide an MBMS service or a DVB-H service to the terminal. [41] Figure 3 is a signal flow chart of a BCAST service method according to an embodiment of the present invention. It is assumed that a user of a terminal 300 has a subscription to one or more BCAST services offered by a home network 100 of the terminal 300 before the user roams to a visiting network 200. The home network 100 may include a BSA unit 110, a BSM unit 120, a BSDA unit 130, and a BDS-SD unit or BDS or IN 140. The visiting network 200 may include a BSA unit 210, a BSM unit 220, a BSDA unit 230, and a BDS-SD unit or BDS or IN 240. The terminal 300 has the same configuration as the terminal 30 in Fig. 1. These components of the system have been discussed in connection with Fig. 1. The home network 100 and the visiting network 200 can be the same brosidcast type networks or different broadcast type networks. All the components of Fig. 3 are operatively coupled. [42] Now, referring to Fig. 3, when the user of the terminal 300, which has roamed from the home network 100 to the visiting network 200, wants to receive a BCAST service at a current position (in the visiting network), the user operates a BCAST application of the terminal 300, and then, the terminal 300 transmits a BCAST service guide request message or a BCAST service request message to the BSM unit 220 of the visiting network 200 (step S11). ThiS request message may include identification in- formation of the user/terminal, etc. [43] The BSM unit 220 informs the BSDA unit 230 of the visiting network about the reception of the BCAST service guide request message or the BCAST service request message through internal communication (step S13), and checks the service au- thentication of the user of the tenrinal (step S15). For instance, a service authorization request message is sent from the BSM unit 220 to the BSM 120 of the home network. In this case, because the BCAST service subscription information of the terminal user (e.g., information on which service or which service bundle the user has subscribed to) exists in the home network 100, the BSM unit 220 of the visiting network requests the subscription information of the user from the BSM unit 120 of the home network (e.g., by transmitting the user/terminal ID, etc.) and performs the service authentication. The service authentication may involve verifying that the current user/terminal is a subscriber to the BCAST service(s) offered by the home network 100. In the al- ternative, the home network 100 may perform the actual service authentication and the visiting network 200 may just receive the result of the service authentication from the home network 100. In this regard, a service authorization response message from the BSM unit 120 to the BSM unit 220 may include the result of the service authentication check and/or other information needed for the subsequent procedures of the visiting network 200. [44] Upon checking the service authentication of the terminal 300, the BSM unit 220 of the visiting network informs the BSDA unit 230 that the service authentication has been completed and the current user/terminal is authorized, through internal com- munication (step S17). At this time, the BSDA unit 230 checks whether there is a wish list for the current user in a server BCAST list stored in the visiting network 200. The server BCAST list is stored in the BCAST server of the visiting network 200, and can exist in the BSA unit 210, in the BSM unit 220 or in the BSDA unit 230, or can be stored in a separate storage unit. The server BCAST list can be managed by the wish list checking application. The server BCAST list includes wish lists of a plurality of different users. A wish list of a user/terminal is the user's preferred BCAST service(s), which can be selected by the user from a list of all the BCAST services offered by the user's home network or from a list of all the BCAST services that the user has subscribed to from the user's home network. The wish list of the terminal may also include other information such as user information, which may be used to generate a service guide. [45] The wish list of the current user may be stored as part of the server BCAST list stored in the visiting network 200. For instance, before the user roams to the visiting network, the visiting network may obtain the wish list of the user in advance through communication with the home network. This can be accomplished in many different ways. For instance, once the user subscribes to the BCAST service(s) of the home network 100 and compiles the user's wish list based on the BCAST service list offered by the home network 100, the home network 100 can be configured to transmit the wish list to the visiting network 200 so that it can be prestored in the visiting network 200. The system can also be configured such that any updated wish list of the user, which is stored in the home network 100 and/or the terminal 300, is communicated to the visiting network 200 from the home network 100 or the terminal 300. [46] In the example of Fig. 3, it is assumed that the wish list of the current terminal 300 does not exist on the visiting network's server. However, the scenario in which the wish list of the current terminal 300 does exist on the visiting network's server, is discussed later in connection with Fig. 4. [47] If the wish list of the terminal 300 does not exist in the server BCAST list at step S17, the BSDA unit 230 of the visiting network transmits a service guide request message to the BSDA unit 130 of the home network 100 (step S19). Then the BSDA unit 130 of the home network collects various information (e.g., subscription in- formation, user's wish list, etc.) for generating a service guide for the current terrninal 300, from the BSM unit 120 and the BSA unit 110 of the home network 100 via internal communication (step S21). Thereafter, the BSDA unit 130 generates the ervice guide (BGAST servic guide) base on the wise list of the current terminal [48] The BSDA unit 130 of the home network transmits the generated service guide to the BSDA unit 230 of the visiting network (step S23), and the BSDA unit 230 of the visiting network transmits the service guide to the terminal 300 (step S25). In this case, the BSDA unit 230 of the visiting network can transmit the service guide received from the B SDA unit 130 of the home network to the terminal 300, or can transmit a new service guide obtained by incorporating a service guide of the visiting network 200 into the service guide received from the BSDA unit 130 of the home network. Namely, the service guide transmitted to the BSDA unit 230 of the visiting network from the BSDA unit 130 of the home network and the service guide transmitted from the BSDA unit 230 of the visiting network to the terminal 300 can be same service guides or different service guides. In step S31, the visiting network 200 broadcasts the service guide to the terminal 300 by using its broadcasting mechanism, e.g., through a broadcast distribution system (e.g., BDS 20 in Fig. 1) or an interaction network (e.g., IT 22 in Fig. 1). [49] When the user checks the BCAST service guide received by the terrninal 300 and selects contents (BCAST service) desired to be received among the programs or services identified in the BCAST service guide, the terminal 300 transmits a BCAST contents request message to the B SDA unit 230 of the visiting network (step S27). In this case, the desired contents are a BCAST service provided in the home network. Thus the BSDA unit 230 of the visiting network transmits the BCAST contents request message to the BSDA unit 130 of the home network (step S27). [50] Upon receiving the BCAST contents request message, the BSDA unit 130 receives contents requested by the user from a contents provider 50 through internal com- munication with the BSA unit 110 (step S29), and transmits the received contents (BCAST service) to the terminal 300 through the BSDA unit 230 of the visiting network (step S31). The visiting network 200 transmits the contents to the terminal 300 by using its broadcasting mechanism. Accordingly, the user roaming in the visiting network receives the BCAST service of the user's home network. [51] Figure 4 is a signal flow chart of a BCAST service method according to another embodiment of the present invention, wherein a current terminal 300 roams to a visiting network 200. The system components discussed in the embodiment of Fig. 3 are also provided in the embodiment of Fig. 4. In Fig. 4, there is a wish list of the current terminal 300 in the server BCAST list of the BCAST server of the visiting network 200, which differs from the embodiment of Fig. 3. The home network 100 and the visiting network 200 can be the same broadcast type networks or different broadcast type networks. It is assumed that the user of the terminal 300 has a sub- scription to one or more BCAST services offered by the home network 100 of the terminal 300 before the user roams to the visiting network 200. All the components of Fig. 4 are operatively coupled. [52] Referring to Fig. 4, when the user of the terminal 300 which has roamed from the home network 100 to the visiting network 200 wants to receive a BCAST service at a current location in the visiting network 200, the user operates a BCAST application of the terminal 300 and transmits a BCAST service guide request message or a BCAST service request message to the BSM unit 220 of the visiting network (step S41). [53] The BSM unit 220 informs the BSDA unit 230 of the visiting network about the reception of the BCAST service guide request message or the BCAST service request message through internal communication (step S43), and checks the service au- thentication of the terminal/user through the BSM unit 120 of the home network (step S45). Steps S41, S43 and S45 correspond respectively to steps S11, S13 and S15 of Fig. 3. [54] Upon checking the service authentication of the terminal/user, the BSM unit 220 of the visiting network informs the BSDA unit 230 that the service authentication of the current terminal 300 has been completed and the current user is authorized to receive the BCAST service, through internal communication (step S47). Then in step S47, the B SDA unit 220 of the visiting network checks whether there is a wish list of the terminal 300 in the server BCAST list. The server BCAST list exists in the BCAST server of the visiting network, and it can exist in the BSA unit 210, in the BSM unit 220 or in the BSDA unit 230, and can be managed by the wish list checking ap- plication. [55] If there is the wish list of the terminal 300 in the server BCAST list of the visiting network, the BSDA unit 230 transmits a BCAST service guide to me terminal 300 (step 49). In this case, the BSDA unit 230 of the visiting network can transmit the BCAST service guide of the home network 100 based on the wish list of the terminal 300 to the terminal 300, or can transmit a new service guide obtained by incorporating the BCAST service guide of the vi siting network 200 to the BCAST service guide of the home network 100, to the terminal 300. In addition, the BSDA unit 230 of the visiting network can collect various information (e.g., BCAST service attribute, etc.) from the BSM unit 220 of the visiting network and the BSA unit 210, for generating a service guide of the terminal 300 based on the wish list of the terminal 300 and generate the BCAST service guide for the terminal 300. The visiting network 200 can transmit the service guide to the terminal 300 by using its broadcasting mechanism, e.g., through a broadcast distribution system (e.g., BDS 20 in Fig. 1) or an interaction network (e.g.,-IT 22 in Fig. 1). [56] When the user checks the BCAST service guide received by the terminal 300 and selects contents desired to be received among programs or services described in the service guide, the terminal 300 transmits a BCAST contents request message to the BSDA unit 130 of the home network through the BSDA unit 230 of the visiting network (step S51). [57] Upon receiving the BCAST contents request message, the BSDA unit 130 of the home network receives contents requested by the user from a contents provider 50 through internal communication with the BSA unit 110 (step S53), and transmits the received contents (BCAST service) to the terminal 300 through the BSDA unit 230 of the visiting network (step S55). The visiting network 200 transmits the BCAST service contents to the terminal 300 by using its broadcasting mechanism. Accordingly, the user roaming in the visiting network receives the BCAST service of the user's home network. [58] Figure 5 is a signal flow chart of a BCAST service method according to another embodiment of the present invention. This embodiment differs from the embodiments of Figs. 3 and 4 in that the visiting network 400 is a non-broadcast type network. Although the visiting network 400 does not directly offer the BCAST service, the terminal user receives the BCAST service through a uni-cast method of the visiting network according to this embodiment. The user of the terminal 300 has subscribed to the BCAST service of the home network before the user roams to the visiting network 400. All the components of Fig. 5 are operatively coupled. [59] As shown in Figure 5, since the non-broadcast type network (visiting network 400) indicated by a wireless network or a mobile communication network does not have an entity for providing the BCAST service, it transmits a service guide and/or contents transmitted from the home network 100 to the current terminal 300 through its packet switched network. That is, communications between the visiting network 400 and the terminal 300 occur using existing communication protocols between the visiting network 400 and the terminal 300. [60] Referring to Fig. 5, when the user of the terminal 300 roams or moves from the user's home network 100 (namely, a broadcast type network) to another network (the visiting network 400, namely a non-broadcast type network), the user operates the BCAST application of the user's terminal 300 and the terminal 300 transmits a BCAST service guide request message or a BCAST service request message to the non- broadcast type visiting network 400 (step S61). [61] Upon receiving the request message, the non-broadcast type visiting network (e.g., a server therein) 400 requests the BSM unit 120 of the home network 100 to check the service authentication of the terminal user (step S63), and the BSM unit 120 of the home network checks the service authentication of the terminal user and transmits a response message including the service authentication result to the non-broadcast type visiting network 400 (step S65). In this case, because the BCAST service subscription information of the terminal user(e.g., information on which service or which servica bundle the user has subscribed to) exists in the home network 100, the visiting network 400 requests the subscription info:rmation of the user from the BSM unit 120 of the home network (e.g., by transmitting the user/terminal ID, etc.) and performs the service authentication. The service authentication may involve verifying that the current user/terminal is a subscriber to the BCAST service(s) offered by the home network 100. In the alternative, the home network 100 may perform the actual service authentication and the visiting network 400 may just receive the result of the service authentication from the home network 100. [62] Upon checking the service authentication of the terminal 300, the non-broadcast type visiting network 400 transmits a service guide request message to the BSDA unit 130 of the home network (step S67). Upon receiving the service guide request message, the BSDA unit 130 of the home network collects service guide information of the terminal 300 from the BSM unit 120 of the home network and the BSA unit 110 through internal communication (step S69). In this case, since the visiting network 400 is a non-broadcast type and thus does not have an entity for providing the BCAST service (via a broadcasting mechanism), the visiting network 400 does not itself have a wish list of the terminal 300 or a service guide with respect to the BCAST service provided from the home network or any other network. Accordingly, the visiting network 400 must obtain the service guide of the terminal 300 from the BSDA unit 130 of the home network, and the BSDA unit 130 of the home network collects the service guide information for the current terminal 300 based on the wish list of the terminal 300 prestored in the home network or provided by the tenninal 300. [63] The BSDA unit 130 of the home network then generates a BCAST service guide for the current terminal 300 using the collected service guide information. The BSDA unit 130 then transmits the generated service guide to the visiting network 400 (step S71), and the visiting network 400 transmits the service guide to the terminal 300 (step S71). In this case, the service guide transmitted by the visiting network 400 to the terminal 300 is the same as the service guide received from the home network 100. [64] When the user checks the BCAST service guide received by the terminal 300 and selects contents desired to be received among programs or services listed in the service guide, the terminal 300 transmits a BCAST contents request message to the BSDA unit 130 of the home network through the visiting network 400 (step S73). [65] Upon receiving the BCAST contents request message, the BSDA unit 130 of the home network receives contents requested by the user from a contents provider 50 through internal communication with the BSA unit 110 (step S75), and transmits the corresponding contents to the terminal 300 through the non-broadcast type visiting network 400 (step S77). In this case, the visiting network 400, which has received the contents, (BCAST service) from the BSD unit 300 of the home network, transmits the contents to the terminal 300 through its packet switched network/method since the visiting network 400 is a non-broadcast type network. Namely, the contents (BCAST service) are transferred by 1:1 through a uni-cast method only between the server of the non-broadcast type visiting network 400 and the terminal 300, e.g., through a data service channel provided in a motile communication network and not through a broadcast distribution system (BDS) or an interaction network. [66] In the embodiment of Fig. 5, if an audio/video codec supported in the network offering the BCAST service (broadcast type network) and an audio/video codec supported in a visiting mobile communication network (non-broadcast type network) do not correspond, a certain transformation process for making the codecs correspond to each other may be used. For example, if the broadcast type network for providing BCAST service contents supports MPEG4 while the mobile communication network (non-broadcast type visiting network) for receiving the BCAST service contents supports MPEG2, not MPEG4, then the mobile communication network is configured to decode the MPEG-4 contents received from the broadcast type network, encode them to MPEG2 and then transmit the MPEG-2 contents to the user terminal. In this case, a procedure for exchanging a contents coding method supported in the broadcast type network and a contents coding method supported in the mobile communication network (non-broadcasting type network) can be added before the contents are provided, and such a procedure is known. In addition, if the home network knows ca- pabilities (for example, a supported codec, a data rate, resolution of a screen of the terminal) of the user's terminal, then corresponding information (e.g., terminars capability information) can be transmitted to the visiting network so that the visiting network can use the information to suitably transform the contents received from the home network before transmitting it to the user's terminal. [67] In the embodiments of Figs. 3-5, it has been described that the wish list of the current user is used to generate the service guide to be provided to the terminal roaming in the visiting network. However, the present invention is not limited thereto, and encompasses a situation where the wish list of the current user is not used to generate the service guide to the current user at the terminal. For instance, without regards to the user's wish list, the service guide, to be provided to the end user at the terminal 300, may be a service guide generated based on the user's subscription policy, or can be a service guide that includes all the BCAST services offered by the home or visiting network. [68] Figure 6 is a signal flow chart of a BCAST service method according to another embodiment of the present invention. In this embodiment, a BCAST service guide is transmitted from a visiting network 200 to a terminal 300 before the terminal requests it. That is, the visiting network, which is abroadcast type network, broadcasts its. service guide repeatedly using its broadcasting mechanism (e.g., BDS or interaction network) to all terminals roamed into the visiting network. Each terminal then can request access (request right objects) to one or more BCAST services on the service guide, and thereby accesses the BCAST service. [69] In Fig. 6, it is assumed that the user of the current terminal 300 has a subscription to one or more (BCAST) services offered by the home network 100 of the terminal 300 before the user roams to the visiting network 200. The home network 100 may include a BSA unit 110, a BSM unit 120, a BSDA unit 130, and a BDS-SD unit or BDS or IN 140. The visiting network 200 may include a BSA unit 210, a BSM unit 220, a BSDA unit 230, and a BDS-SD unit or BDS or IN 240. These components have been discussed in connection with Fig. 1. The home network 100 and the visiting network 200 can be the same broadcast type networks or different broadcast type networks. All the components of Fig. 6 are operatively coupled. [70] Now, referring to Fig. 6, the terminal 300, which has roamed to the visiting network 200, receives a BCAST service guide of the visiting network 200 from the BSDA unit 230 of the visiting network, without being connected with the home network 100 (step S81). Namely, the visiting network 200 provides its service guide to the terminal 300 which has roamed to the visiting network 200, without the user's request and without any contact with the home network 100. This may be accomplished by the visiting network 200 by repeatedly broadcasting its service to all terminals that roamed into the visiting network 200, e.g., using its broadcasting mechanism. [71] Upon checking the service guide, the user requests a use privilege (access in- formation, e.g., right object(s) RO) in order to access a specific BCAST service identified in the service guide from the BSM unit 220 of the visiting network (step S83). The use privilege is a right with respect to contents requested by the user or a right for accessing or using the BCAST service. The BSM unit 220 of the visiting network receives this request and also checks the service authentication of the cor- responding terminal 300 from the BSM unit 120 of the home network. Namely, the BSM unit 220 of the visiting network transmits a service authentication request message to the BSM unit 120 of the home network (step S85), and the BSM unit 120 of the home network checks the service authentication of the terminal and transmits a service authentication response message to the BSM unit 220 of the visiting network (step S87). The service authentication response message includes the result of the service authentication. The service authentication may involve detenriining whether or not the current terminal 300 is a subscriber of the home network 100, and examining in detail the subscription policy of ths user of the terminal 300 so as to determine whether or not the user should receive the specific BCAST service requested by the user at step S81. The actual service authentication can be performed by the home network 100, or the visiting network, or in part by the home network and in part by the visiting network. [72] If the service authentication result indicates that the terminal 300 is authorized to receive the BCAST service, the BSM unit 220 of the visiting network transmits the use privilege (access information such as RO) for allowing access and/or use of the specific BCAST service requested by the user, to the user (step S89). RO can be a key or code to open or decrypt the BCAST service (contents). The BSDA unit 230 of the visiting network transmits the user-requested contents (BCAST service) to the terminal 300 through its broadcasting mechanism (step S91). In this case, the BSDA unit 230 and the BSM unit 220 may transmit or exchange information and signals through internal communication. [73] Upon receiving the contents, the terminal 300 accesses or interprets the received contents by using the RO. The BSM unit 220 of the visiting network generates charging (billing) information (e.g., charges regarding the use of the contents, etc.) according to the use of the corresponding contents (S93), and the visiting network 200 can send the generated charging information to the home network 100 so that the user can be billed appropriately by the home network. The visiting network 200 sends the charging information to the home network 100 for the services the visiting network provided since the user has a subscription contract with the home network 100. The charging information may include any other service fee of the visiting network 200 for allowing the roaming user to receive a BCAST service. [74] According to the present invention, the step of generating the charging information in step S93 may also be performed in other embodiments, e.g., in the embodiments of Figs. 3-5. For instance, if the visiting network merely passes on the BCAST service contents provided by the home network, the charging information may include any service fee of the visiting network 200 for merely passing on the BCAST service contents. [75] As so far described, the broadest/multicast service system and method for supporting inter-network roaming in accordance with the embodiments of the present invention have many advantages. [76] For example, after the terminal roams into a visiting network, it can now receive the same BCAST service as the BCAST service that the terminal has received in the home network, at a current location in the visiting network. [77] In addition, because the user can set and receive his/her preferred BCAST service with continuity regardless of its position (e.g., whether the user is currently located in the home network or visiting network), the user's convenience and satisfaction for receiving the BCAST service can be enhanced greatly. [78] Theforegoing embodiments and advantage are merely exemplary and are not to be construed as limiting the present invention. The present teaching can be readily applied to other types of apparatuses or systems. The description of the preferred embodiments of the present invention is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. In the claims, means-plus-function clauses are intended to cover the structure described herein as performing the recited function and not only structural equivalents but also equivalent structures. WE CLAIM: 1. A method of providing a broadcast/multicast (BCAST) service when a terminal roams from a home network to a visited network, the method comprising the steps of: generating, by a BCAST service distribution/adaptation (BSDA) unit of the visited network, a BCAST service guide for the terminal based on a wish list of the terminal, wherein said wish list of the terminal is a user's preferred BCAST services, which can be selected by the user from a. list of all the BCAST services offered by the user's home network or from a list of all the BCAST services that the user has subscribed to from the user's home network; transmitting, by the BSDA unit of the visited network, the BCAST service guide to the terminal; receiving, by a BCAST subscription management (BSM) unit of the visited network, a request from the terminal to access at least one BCAST service based on the service guide; transmitting, by the BSM unit of the visited network, a service authorization request to a BSM unit of the home network; receiving, by the BSM unit of the visited network, a service authorization response from the BSM unit of the home network in response to the service aumorization request; transmitting, by the BSM unit of the visited network to the terminal, at least one rights object (RO) to access the at least one BCAST service, wherein the RO comprises a key or code used to open or decrypt contents of the at least one BCAST service; and providing, by the BSDA unit of the visited network, the at least one BCAST service to the terminal. 2. The method as claimed in claim 1, wherein the step of transmitting the BCAST service guide and the step of providing the at least one BCAST service are performed via a broadcast distribution system (BDS) that cooperates with the BSDA unit. 3. The method as claimed in claim 2, wherein the BDS supports a bearer providing the BCAST service and supports at least one among a group of technologies comprising DVB-H, MBMS, BCMCS, ISDB-T, and DMB. 4. The method as claimed in claim 3, wherein the BSDA unit of the visited network provides the BCAST service guide to the terminal by repeatedly broadcasting said BCAST service guide to terminals that roamed into the visited network without having to receive any user request or without having to receive the same or different BCAST service guide from the home network. 5. The method as claimed in claim 4, wherein the BCAST service guide is provided by the BSDA unit of the visited, network and is provided independently of the same or different BCAST service guide provided by a BSDA of the home network. 6. A visited network that provides a broadcast/multicast (BCAST) service when a terminal roams to the visited network, the visited network comprising: a BCAST service distribution/adaptation (BSDA) unit of the visited network, adapted to: generate a BCAST service guide for the terminal based on a wish list of the terminal, wherein said wish list of the terminal is a user's preferred BCAST services, which can be selected by the user from a list of all the BCAST services offered by the user's home network or from a list of all the BCAST services mat the user has subscribed to from the user's home network, transmit the BCAST service guide to the terminal, and provide at least one BCAST sendce to the terminal; and a BCAST subscription management (BSM) unit adapted to: receive a request from the terminal to access at least one BCAST service based on the service guide, transmitting a service authorization request to a BSM unit of a home network of the terminal, receive a service authorization response from the home network of the terminal in response to the service audiorization request, and transmit at least one rights object (RO) for accessing the at least one BCAST service to the terminal, wherein the RO comprises a key or code used to open or decrypt contents of the at least one BCAST service to the terminal. 7. The network as claimed in claim 6, wherein the BSDA unit cooperates with a broadcast distribution system (BDS) in the network to provide the service guide and provide the BCAST service. 8. The network as claimed in claim 7, wherein the BDS supports a bearer providing the BCAST service and supports at least one among a group of technologies comprising DVB-H, MBMS, BCMCS, ISDB-T, and DMB. 9. The network as claimed in claim 8, wherein the BSDA unit of the visited network is adapted to provide the BCAST service guide to the terminal by repeatedly broadcasting said BCAST service guide to terminals that roamed into the visited network without having to receive any user request or without having to receive the same or different BCAST service guide from the home network. 10. The network as claimed in claim 9, wherein the BCAST service guide is provided by the BSDA unit of the visited network and is provided independendy of the same or different BCAST service guide provided by a BSDA of the home network. ABSTRACT BROADCAST/MULTICAST SERVICE SYSTEM AND METHOD PROVIDING ESTER-NETWORK ROAMING A method and system for providing a broadcast/multicast (BCAST) service, are provided to guarantee continuity of the BCAST service even when a user roams in the same network or between different networks. The method involves transmitting a BCAST service guide to terminal 300 (S81), receiving a request from the terminal 300 to access at least one BCAST service based on the service guide (S83), transmitting a service authorization request to a BSM unit 120 of a home network 100 (S85), receiving a service authorization response from the BSM unit 120 of the home network 100 (S87) in response to the service authorization request, transmitting to the terminal 300 at least one rights object (RO) to access the at least one BCAST service (S89), and providing the at least one BCAST service to the terminal 300 (S91).

Full Text

Technical Field
The present invention relates to a mobile communication system and, more par-
ticularly, to a broadcast/multicast service system and method supporting inter-network
roaming in order to provide a broadcast/multicast service to a user when the user roams
in a visiting network which may or may not be a broadcast type network.
Background Art
A broadcast/multicast service (referred to hereinafter as 'BCAST service') is a new
type of service that provides a sky wave broadcast or supplementary information to a
mobile terminal. The BCAST service includes both a broadcast service and a multicast
service. A broadcast service, offered by a service provider, transmits usable in-
formation to' every user who has subscribed to the services of the service provider. A
multicast service, also offered by a service provider, transmits information only to a
certain group of users who have subscribed for a specific subject or contents.
Currently, in the mobile communication network, a simple service is provided to
provide simple information to users:, but the BCAST service providing a multimedia
type broadcast or various contents to users roaming in the mobile communication
network is not provided yet
Further, in a situation where the BCAST service is independently operated by each
BCAST service provider, if a user who has subscribed to a specific service provider is
moved to an area of a different service provider, continuity of the BCAST service for
the user is not provided.
In addition, when the user who has subscribed for a specific BCAST service with
the user's home network roams to a. visiting network, there is no procedure, system or
mechanism by which the BCAST service contents of the home network are provided to
the user roaming in the visiting network. If the visiting network is a non-broadcast type
network or is a broadcast type network which may be the same type as or different
from the home network, there is no defined procedure by which the user roaming in the
visiting network can obtain the BCAST service of the home network or the BCAST
service of the visiting network. This inconveniences the user greatly.
Disclosure of Invention
Technical Problem
Therefore, one object of the present invention is to provide a broadcast/multicast ser
vice (BCAST) system and method supporting inter-network roaming, which are

capable of guaranteeing continuity of a broadcast/multicast service even when a user
roams in the same service network or in a different service network.
[7] Another object of the present invention is to provide a broadcast/multicast service
system and method supporting inter-network roaming, which are capable of allowing a
user who has roamed from a home network to a visiting network to receive a
broadcast/multicast service by using a service supported in the visiting network.
[8] Still another object of the present invention is to provide a broadcast/multicast
service system and method capable of allowing a mobile terminal to use a service
provided in a home network when the terminal roams among broadcast type networks.
[9] Yet another object of the present invention is to provide a broadcast/multicast
service system and method capable of allowing a mobile terminal to use a broadcast/
multicast service through a non-broadcast type network when the terminal roams from
a broadcast type network into a non-broadcast type network,
[10] Another object of the present invention is to provide a mobile terminal, a system, a
method, and computer software embodied on at least one computer-readable medium ....'...-
for implementing the method, for providing a BCAST service to an end user/terminal
roaming in a visiting network, which overcome limitations and disadvantages
associated with the background art.
[11] According to an aspect of the present invention, there is provided a method of
providing a broadcast/multicast (BCAST) service to a terminal, the method
comprising: obtaining, by the terminal, at least one BCAST service from a visiting
network when the terminal roams in the visiting network.
[12] According to an aspect of the present invention, there is provided a method of
obtaining a broadcast/multicast (BCAST) service when a terminal moves from a home
network, the method comprising: receiving, by the terminal BCAST service guide in-
formation from the visiting network; transmitting, by the terminal, a request to access
at least one BCAST service provided in the BCAST service guide information; and
obtaining the at least one BCAST service from the visiting network.
[13] According to an aspect of the present invention, there is provided a mobile terminal
device for obtaining a broadcast/multicast (BCAST) service while roaming in a
visiting network, the device comprising: a controller to receive BCAST service guide
information from the visiting network, to transmit a request to access at least one
BCAST service provided in the BCAST service guide information to the visiting
network, and to obtain the at least one BCAST service from the visiting network.
[14] According to an aspect of the present invention, there is provided a broadcast/
multicast (BCAST) system comprising: a terminal, a home network of the terminal and
configured to communicate with me terminal, and a visiting network configured to
communicate with the home network and the terminal, wherein the terminal obtains at

least one BCAST service from the visiting network when the terminal roams in the
visiting network
According to an aspect of the present invention, there is provided a method of
providing a broadcast/multicast (BCAST) service when a terminal roams to a visiting
network, the method comprising: providing, by a BCAST service distribution/
adaptation (BSDA) unit of the visiting network, a service guide to the terminal;
transmittingr by the terminal, a request to access at least one BCAST service to a
BCAST subscription management (BSM) unit of the visiting network; transmitting, by
the BSM unit of the visiting network, a service authorization request to a BSM unit of
a home network of the terminal; receiving, by the BSM of the visiting network, a
. service authorization response form the BSM unit of the home network in response to
the service authorization request; transmitting, by the BSM unit of the visiting,
network, at least one right object for accessing the at least one BCAST service to the
terminal; and providing, by the BSD A unit of the visiting network, the at least one
BCAST service to the terminal.
Additional advantages, obj ects, and features of the invention will be set forth in part
in the description which follows and in part will became apparent to those having
ordinary skill in the art upon examination of the following or may be learned from
practice of the invention. The objects and advantages of the invention may be realized
and attained as particularly pointed out in the appended claims.
Brief Description of the Accompanying Drawings
The invention will be described in detail with reference to thefoUowing drawings in
which like reference numerals refer to like elements wherein:
Figure 1 is a block diagram showing the construction of a BCAST service system
according to an embodiment of the present invention;
Figure 2 illustrates three examples in which a terminal roams from a home network
to a visiting network and receives, a BCAST service in the visiting network according
to embodiments of the present invention;
Figure 3 is a signal flow chart of a BCAST service method wherein a terminal
roams from a home network to a visiting network in accordance with a first
embodiment of the present invention;
Figure 4 is a signal flow chart, of a BCAST service method wherein a terminal
roams from a home network to a visiting network in accordance with a second
embodiment of the present invention;
Figure 5 is signal flow chart of a BCAST service method wherein a terminal roams
from a home network to a visiting network in accordance with a third embodiment of
the present invention; and
Hgure 6 is signal flow chart of a BCAST service method wherein a terminal roams

from a home network to a visiting network in accordance with a fourth embodiment of
the present invention.
Mode for Invention
[24] A broadcast/multicast (BCAST) service system and method that provide inter-
network roaming in accordance with preferred embodiments of the present invention
will now be described with reference to the accompanying drawings.
[25] In the present invention, when a user (having a mobile terminal) who has
subscribed to a BCAST service offered by a home network of the terminal roams from
the home network to a visiting network, the user can receive, in the visiting network,
the same BCAST service that is provided in the home network. In this case, the
visiting network may transmit a service guide of the home network to the user in the
visiting network, or incorporate the service guide of the home network with the visiting
network's service guide and transmits it to the user in the visiting network.
[26] In the present invention, when a user who has subscribed to a specific BCAST
service roams from the user's home network to a visiting network, the visiting network
checks service authentication of the user from the home network and provides a public
key (right object) used to view contents of the BCAST service in the visiting network,
to the terminal of the user.
[27] In the present invention, when a user who has subscribed to a specific BCAST
service roams from a broadcast type network to another same broadcast type network,
or to a different broadcast type network, or to a non-broadcast type network, the user
can still receive the BCAST service through the roamed network.
[28] Figure 1 is a block diagram showing the construction of a BCAST service system
according to an embodiment of the present invention. All the components of the
BCAST service system are operatively coupled.
[29] As shown in Figure 1, the BCAST service system includes a contents provider
(content creation) 10 for providing contents to distribute in the BCAST service, a
broadcast/multicast (BCAST) server 17 for providing a BCAST service to a user or
performing protection of the contents or mamtaining/rnanaging the BCAST service,
and a terminal 30 for receiving a BCAST service selected by the user from the BCAST
server 17. The terminal 30 is a mobile terminal such as a mobile phone, a PDA, etc.
and includes known elements including an input unit (e.g., a keypad, buttons, etc.), a
controller, a memory, etc.
[30] The BCAST service system additionally includes a broadcast distribution system
(BDS) 20 or an interaction network (IN) 22 for distributing the BCAST service and
performing an interaction function for bi-directional communication, and/or a BDS
service distribution (BDS-SD) unit 18 for applying the interaction network according
to a bearer. The units 18, 20 and 22 are involved in distributing the BCAST service

contents provided by the server 17 to an appropriate device such as the terminal 30 or a
home or visiting network.
[31] The BDS 20 or the interaction network 22 is a bearer providing a BCAST service
such as a DVB-H (Digital Video Broadcasting-Handled), an MBMS (Multimedia
Broadcast Multicast Service), a BCMCS (Broadcast Multicast Service), an ISDB-T
(Integrated Service Digital Broadcasting-Terrestrial), or a T/S DMB
(Terrestrial/Satellite-Digital Multimedia Broadcasting). Thus the BDS 20 and the in-
teraction network 22 support the broadcasting mechanism.
[32] The BCAST server 17 includes a BCAST service application (BSA) unit 12 for
performing functions such as protecting BCAST service contents and/or mamtaining/
managing the BCAST service, a BCAST service distribution/adaptation (BSDA) unit
14 for performing and controlling broadcasting, interface and contents scheduling
function by using a specific bearer (DVB-H, MBMS, BCMCS, etc.), and a BCAST
subscription management (BSM) unit 16 for performing functions of protecting/
managing service/contents and maintaining/managing user subscription information inorder to manage users who have subscribed to the BCAST service. In this case, the
BSA unit 12, the BCAST service distribution/adaptation unit 14 and the BCAST sub-
scription/management unit 16 of ths BCAST server 17 transmit or exchange in-
formation and signals to each other or with each other through internal communication.
Communications from the BSDA unit 14 and the BSM unit 16 may be communicated
to a final destination device (e.g., the terminal 30) directly or through one or more of
the BDS-SD unit 18, the BDS 20, and the interaction network 22.
[33] The terminal 30 includes an application/software for receiving the BCAST service
and an application for storing and editing a portion of a BCAST service list provided
by the BCAST service provider and storing information on a channel preferred by the
user. A BCAST service preference list edited and generated by the user by reflecting
the preferences of the user based on the BCAST service list provided; by the service
provider is called a wish list. The terminal 30 and its associated network (e.g., the
home network) may include an application for managing the wish list, which is called
a wish list management application. The terminal 30 can be a mobile phone, a PDA,
etc., but is not limited thereto and can be any device that is configured to receive
BCAST services.
[34] The wish list management application manages the wish list separately, and when a
user of a terminal who has subscribed to a service of a specific provider roams to a
service area of a different provider and receives a different BCAST service list
provided by the corresponding provider, the wish list management application stores
and edits a portion of the wish list. When the service provider of the visiting network
to which the user has roamed does not provide a service list with respect to the BCAST

provided in the terminal's home network, the wish list management application
receives the service list from the home network in advance and stores it, or stores a
service selected by the user among the provided service list in the wish list in advance.
[35] A service provider providing a specific service can transfer a list of services
provided in a network of a different service provider with which the service provider
has made a roaming contract as well as a list of services provided in its own network.
In this case, the service provider should indicate that the service is a service provided
by a different provider and not by the service provider itself. Namely, the BCAST
server includes a wish list checking application which fetches a wish list of the user's
terminal and checks whether the BCAST server can currently provide any service on
the wish list, and if the BCAST service cannot provide the services on the wish list, it
checks whether a different provider or a different server can provide it.
[36] The wish list checking application may exist in every BCAST server, and when a
roaming contact exists between service providers, wish list checking applications in the
BCAST servers of different providers can interwork so that a service requested by theuser can be provided among BCAST services provided by each BCAST server. It
should be noted that 'a wish list of the terminal' and 'a wish list of the user' refer to the
same and are used below interchangeably.
[37] The BCAST server 17 periodically can check the wish list of the terminal 30 and
store it as part of the server 17's stored service broadcast list (server BCAST list)
therein or in a separate storage unit outside the BCAST server. The BCAST server 17
can store therein (or in a separate storage unit) information on services which have
been provided by different service providers to each requesting user. Thus, when a
certain user requests a BCAST service thereafter, the BCAST server 17 searches its
storage unit and obtains the current user's history of the BCAST service. And this in-
formation can be used by the BCAST server or others to provide the requested BCAST
service to the current user more easily and quickly. In addition, even if the user does
not provide the user's wish list to the BCAST server, since the BCAST server stores
the corresponding information, the BCAST service can be provided to the user.
[38] Figure 2 illustrates three different examples in which a terminal may roam and still
receive a BCAST service according to the embodiments of the present invention.
[39] As shown in Fig. 2, a user of the terminal can roam between the same broadcast
type networks (e.g., between MBMSs), can roam between different broadcast type
networks (e.g., between the MBMS and the DVB-H), or can roam between a broadcast
type network and a non-broadcast type network. In the third example, the broadcast
type network is not limited to the MBMS or the DVB-H, but can be the BCMCS,
ISDB-T, T/S-DMB, or others, and the non-broadcast type network can be the GSM or
CDMA, which does not directly offer the BCAST service or does not support the

broadcasting mechanism.
[40] In some embodiments of the present invention, when the terminal (user) has
subscribed to one or more BCAST services of a home network and roams to another
network (visiting network) which may be the same type of broadcast network or a
different type of broadcast network the visiting network is configured to provide the
BCAST service of the home network to the terminal by obtaining the BCAST service
of the home network and broadcasting the BCAST service (contents) to the terminal in
the visiting network. In another embodiment, the BCAST service of the visiting
network may be provided to the terminal roaming in the visiting network, once the
visiting network performs a service authorization check of the terminal through the
home network of the terminal. Further, even if the visiting network is a non-broadcast
type network, which does not support the broadcasting mechanism, the visiting
network can still provide the BCAST service of the home network to the terminal
roaming in the visiting network using a unitcast method. For example, even if the
visiting network is a non-broadcast type network and only provides a general mobile
communication service, the visiting network can still provide an MBMS service or a
DVB-H service to the terminal.
[41] Figure 3 is a signal flow chart of a BCAST service method according to an
embodiment of the present invention. It is assumed that a user of a terminal 300 has a
subscription to one or more BCAST services offered by a home network 100 of the
terminal 300 before the user roams to a visiting network 200. The home network 100
may include a BSA unit 110, a BSM unit 120, a BSDA unit 130, and a BDS-SD unit or
BDS or IN 140. The visiting network 200 may include a BSA unit 210, a BSM unit
220, a BSDA unit 230, and a BDS-SD unit or BDS or IN 240. The terminal 300 has
the same configuration as the terminal 30 in Fig. 1. These components of the system
have been discussed in connection with Fig. 1. The home network 100 and the visiting
network 200 can be the same brosidcast type networks or different broadcast type
networks. All the components of Fig. 3 are operatively coupled.
[42] Now, referring to Fig. 3, when the user of the terminal 300, which has roamed from
the home network 100 to the visiting network 200, wants to receive a BCAST service
at a current position (in the visiting network), the user operates a BCAST application
of the terminal 300, and then, the terminal 300 transmits a BCAST service guide
request message or a BCAST service request message to the BSM unit 220 of the
visiting network 200 (step S11). ThiS request message may include identification in-
formation of the user/terminal, etc.
[43] The BSM unit 220 informs the BSDA unit 230 of the visiting network about the
reception of the BCAST service guide request message or the BCAST service request
message through internal communication (step S13), and checks the service au-

thentication of the user of the tenrinal (step S15). For instance, a service authorization
request message is sent from the BSM unit 220 to the BSM 120 of the home network.
In this case, because the BCAST service subscription information of the terminal user
(e.g., information on which service or which service bundle the user has subscribed to)
exists in the home network 100, the BSM unit 220 of the visiting network requests the
subscription information of the user from the BSM unit 120 of the home network (e.g.,
by transmitting the user/terminal ID, etc.) and performs the service authentication. The
service authentication may involve verifying that the current user/terminal is a
subscriber to the BCAST service(s) offered by the home network 100. In the al-
ternative, the home network 100 may perform the actual service authentication and the
visiting network 200 may just receive the result of the service authentication from the
home network 100. In this regard, a service authorization response message from the
BSM unit 120 to the BSM unit 220 may include the result of the service authentication
check and/or other information needed for the subsequent procedures of the visiting
network 200.
[44] Upon checking the service authentication of the terminal 300, the BSM unit 220 of
the visiting network informs the BSDA unit 230 that the service authentication has
been completed and the current user/terminal is authorized, through internal com-
munication (step S17). At this time, the BSDA unit 230 checks whether there is a wish
list for the current user in a server BCAST list stored in the visiting network 200. The
server BCAST list is stored in the BCAST server of the visiting network 200, and can
exist in the BSA unit 210, in the BSM unit 220 or in the BSDA unit 230, or can be
stored in a separate storage unit. The server BCAST list can be managed by the wish
list checking application. The server BCAST list includes wish lists of a plurality of
different users. A wish list of a user/terminal is the user's preferred BCAST service(s),
which can be selected by the user from a list of all the BCAST services offered by the
user's home network or from a list of all the BCAST services that the user has
subscribed to from the user's home network. The wish list of the terminal may also
include other information such as user information, which may be used to generate a
service guide.
[45] The wish list of the current user may be stored as part of the server BCAST list
stored in the visiting network 200. For instance, before the user roams to the visiting
network, the visiting network may obtain the wish list of the user in advance through
communication with the home network. This can be accomplished in many different
ways. For instance, once the user subscribes to the BCAST service(s) of the home
network 100 and compiles the user's wish list based on the BCAST service list offered
by the home network 100, the home network 100 can be configured to transmit the
wish list to the visiting network 200 so that it can be prestored in the visiting network

200. The system can also be configured such that any updated wish list of the user,
which is stored in the home network 100 and/or the terminal 300, is communicated to
the visiting network 200 from the home network 100 or the terminal 300.
[46] In the example of Fig. 3, it is assumed that the wish list of the current terminal 300
does not exist on the visiting network's server. However, the scenario in which the
wish list of the current terminal 300 does exist on the visiting network's server, is
discussed later in connection with Fig. 4.
[47] If the wish list of the terminal 300 does not exist in the server BCAST list at step
S17, the BSDA unit 230 of the visiting network transmits a service guide request
message to the BSDA unit 130 of the home network 100 (step S19). Then the BSDA
unit 130 of the home network collects various information (e.g., subscription in-
formation, user's wish list, etc.) for generating a service guide for the current terrninal
300, from the BSM unit 120 and the BSA unit 110 of the home network 100 via
internal communication (step S21). Thereafter, the BSDA unit 130 generates the
ervice guide (BGAST servic guide) base on the wise list of the current terminal
[48] The BSDA unit 130 of the home network transmits the generated service guide to
the BSDA unit 230 of the visiting network (step S23), and the BSDA unit 230 of the
visiting network transmits the service guide to the terminal 300 (step S25). In this case,
the BSDA unit 230 of the visiting network can transmit the service guide received
from the B SDA unit 130 of the home network to the terminal 300, or can transmit a
new service guide obtained by incorporating a service guide of the visiting network
200 into the service guide received from the BSDA unit 130 of the home network.
Namely, the service guide transmitted to the BSDA unit 230 of the visiting network
from the BSDA unit 130 of the home network and the service guide transmitted from
the BSDA unit 230 of the visiting network to the terminal 300 can be same service
guides or different service guides. In step S31, the visiting network 200 broadcasts the
service guide to the terminal 300 by using its broadcasting mechanism, e.g., through a
broadcast distribution system (e.g., BDS 20 in Fig. 1) or an interaction network (e.g.,
IT 22 in Fig. 1).
[49] When the user checks the BCAST service guide received by the terrninal 300 and
selects contents (BCAST service) desired to be received among the programs or
services identified in the BCAST service guide, the terminal 300 transmits a BCAST
contents request message to the B SDA unit 230 of the visiting network (step S27). In
this case, the desired contents are a BCAST service provided in the home network.
Thus the BSDA unit 230 of the visiting network transmits the BCAST contents request
message to the BSDA unit 130 of the home network (step S27).
[50] Upon receiving the BCAST contents request message, the BSDA unit 130 receives
contents requested by the user from a contents provider 50 through internal com-

munication with the BSA unit 110 (step S29), and transmits the received contents
(BCAST service) to the terminal 300 through the BSDA unit 230 of the visiting
network (step S31). The visiting network 200 transmits the contents to the terminal 300
by using its broadcasting mechanism. Accordingly, the user roaming in the visiting
network receives the BCAST service of the user's home network.
[51] Figure 4 is a signal flow chart of a BCAST service method according to another
embodiment of the present invention, wherein a current terminal 300 roams to a
visiting network 200. The system components discussed in the embodiment of Fig. 3
are also provided in the embodiment of Fig. 4. In Fig. 4, there is a wish list of the
current terminal 300 in the server BCAST list of the BCAST server of the visiting
network 200, which differs from the embodiment of Fig. 3. The home network 100 and
the visiting network 200 can be the same broadcast type networks or different
broadcast type networks. It is assumed that the user of the terminal 300 has a sub-
scription to one or more BCAST services offered by the home network 100 of the
terminal 300 before the user roams to the visiting network 200. All the components of
Fig. 4 are operatively coupled.
[52] Referring to Fig. 4, when the user of the terminal 300 which has roamed from the
home network 100 to the visiting network 200 wants to receive a BCAST service at a
current location in the visiting network 200, the user operates a BCAST application of
the terminal 300 and transmits a BCAST service guide request message or a BCAST
service request message to the BSM unit 220 of the visiting network (step S41).
[53] The BSM unit 220 informs the BSDA unit 230 of the visiting network about the
reception of the BCAST service guide request message or the BCAST service request
message through internal communication (step S43), and checks the service au-
thentication of the terminal/user through the BSM unit 120 of the home network (step
S45). Steps S41, S43 and S45 correspond respectively to steps S11, S13 and S15 of
Fig. 3.
[54] Upon checking the service authentication of the terminal/user, the BSM unit 220 of
the visiting network informs the BSDA unit 230 that the service authentication of the
current terminal 300 has been completed and the current user is authorized to receive
the BCAST service, through internal communication (step S47). Then in step S47, the
B SDA unit 220 of the visiting network checks whether there is a wish list of the
terminal 300 in the server BCAST list. The server BCAST list exists in the BCAST
server of the visiting network, and it can exist in the BSA unit 210, in the BSM unit
220 or in the BSDA unit 230, and can be managed by the wish list checking ap-
plication.
[55] If there is the wish list of the terminal 300 in the server BCAST list of the visiting
network, the BSDA unit 230 transmits a BCAST service guide to me terminal 300

(step 49). In this case, the BSDA unit 230 of the visiting network can transmit the
BCAST service guide of the home network 100 based on the wish list of the terminal
300 to the terminal 300, or can transmit a new service guide obtained by incorporating
the BCAST service guide of the vi siting network 200 to the BCAST service guide of
the home network 100, to the terminal 300. In addition, the BSDA unit 230 of the
visiting network can collect various information (e.g., BCAST service attribute, etc.)
from the BSM unit 220 of the visiting network and the BSA unit 210, for generating a
service guide of the terminal 300 based on the wish list of the terminal 300 and
generate the BCAST service guide for the terminal 300. The visiting network 200 can
transmit the service guide to the terminal 300 by using its broadcasting mechanism,
e.g., through a broadcast distribution system (e.g., BDS 20 in Fig. 1) or an interaction
network (e.g.,-IT 22 in Fig. 1).
[56] When the user checks the BCAST service guide received by the terminal 300 and
selects contents desired to be received among programs or services described in the
service guide, the terminal 300 transmits a BCAST contents request message to the
BSDA unit 130 of the home network through the BSDA unit 230 of the visiting
network (step S51).
[57] Upon receiving the BCAST contents request message, the BSDA unit 130 of the
home network receives contents requested by the user from a contents provider 50
through internal communication with the BSA unit 110 (step S53), and transmits the
received contents (BCAST service) to the terminal 300 through the BSDA unit 230 of
the visiting network (step S55). The visiting network 200 transmits the BCAST service
contents to the terminal 300 by using its broadcasting mechanism. Accordingly, the
user roaming in the visiting network receives the BCAST service of the user's home
network.
[58] Figure 5 is a signal flow chart of a BCAST service method according to another
embodiment of the present invention. This embodiment differs from the embodiments
of Figs. 3 and 4 in that the visiting network 400 is a non-broadcast type network.
Although the visiting network 400 does not directly offer the BCAST service, the
terminal user receives the BCAST service through a uni-cast method of the visiting
network according to this embodiment. The user of the terminal 300 has subscribed to
the BCAST service of the home network before the user roams to the visiting network
400. All the components of Fig. 5 are operatively coupled.
[59] As shown in Figure 5, since the non-broadcast type network (visiting network 400)
indicated by a wireless network or a mobile communication network does not have an
entity for providing the BCAST service, it transmits a service guide and/or contents
transmitted from the home network 100 to the current terminal 300 through its packet
switched network. That is, communications between the visiting network 400 and the

terminal 300 occur using existing communication protocols between the visiting
network 400 and the terminal 300.
[60] Referring to Fig. 5, when the user of the terminal 300 roams or moves from the
user's home network 100 (namely, a broadcast type network) to another network (the
visiting network 400, namely a non-broadcast type network), the user operates the
BCAST application of the user's terminal 300 and the terminal 300 transmits a BCAST
service guide request message or a BCAST service request message to the non-
broadcast type visiting network 400 (step S61).
[61] Upon receiving the request message, the non-broadcast type visiting network (e.g.,
a server therein) 400 requests the BSM unit 120 of the home network 100 to check the
service authentication of the terminal user (step S63), and the BSM unit 120 of the
home network checks the service authentication of the terminal user and transmits a
response message including the service authentication result to the non-broadcast type
visiting network 400 (step S65). In this case, because the BCAST service subscription
information of the terminal user(e.g., information on which service or which servica
bundle the user has subscribed to) exists in the home network 100, the visiting network
400 requests the subscription info:rmation of the user from the BSM unit 120 of the
home network (e.g., by transmitting the user/terminal ID, etc.) and performs the
service authentication. The service authentication may involve verifying that the
current user/terminal is a subscriber to the BCAST service(s) offered by the home
network 100. In the alternative, the home network 100 may perform the actual service
authentication and the visiting network 400 may just receive the result of the service
authentication from the home network 100.
[62] Upon checking the service authentication of the terminal 300, the non-broadcast
type visiting network 400 transmits a service guide request message to the BSDA unit
130 of the home network (step S67). Upon receiving the service guide request
message, the BSDA unit 130 of the home network collects service guide information
of the terminal 300 from the BSM unit 120 of the home network and the BSA unit 110
through internal communication (step S69). In this case, since the visiting network 400
is a non-broadcast type and thus does not have an entity for providing the BCAST
service (via a broadcasting mechanism), the visiting network 400 does not itself have a
wish list of the terminal 300 or a service guide with respect to the BCAST service
provided from the home network or any other network. Accordingly, the visiting
network 400 must obtain the service guide of the terminal 300 from the BSDA unit
130 of the home network, and the BSDA unit 130 of the home network collects the
service guide information for the current terminal 300 based on the wish list of the
terminal 300 prestored in the home network or provided by the tenninal 300.
[63] The BSDA unit 130 of the home network then generates a BCAST service guide for

the current terminal 300 using the collected service guide information. The BSDA unit
130 then transmits the generated service guide to the visiting network 400 (step S71),
and the visiting network 400 transmits the service guide to the terminal 300 (step S71).
In this case, the service guide transmitted by the visiting network 400 to the terminal
300 is the same as the service guide received from the home network 100.
[64] When the user checks the BCAST service guide received by the terminal 300 and
selects contents desired to be received among programs or services listed in the service
guide, the terminal 300 transmits a BCAST contents request message to the BSDA unit
130 of the home network through the visiting network 400 (step S73).
[65] Upon receiving the BCAST contents request message, the BSDA unit 130 of the
home network receives contents requested by the user from a contents provider 50
through internal communication with the BSA unit 110 (step S75), and transmits the
corresponding contents to the terminal 300 through the non-broadcast type visiting
network 400 (step S77). In this case, the visiting network 400, which has received the
contents, (BCAST service) from the BSD unit 300 of the home network, transmits the
contents to the terminal 300 through its packet switched network/method since the
visiting network 400 is a non-broadcast type network. Namely, the contents (BCAST
service) are transferred by 1:1 through a uni-cast method only between the server of
the non-broadcast type visiting network 400 and the terminal 300, e.g., through a data
service channel provided in a motile communication network and not through a
broadcast distribution system (BDS) or an interaction network.
[66] In the embodiment of Fig. 5, if an audio/video codec supported in the network
offering the BCAST service (broadcast type network) and an audio/video codec
supported in a visiting mobile communication network (non-broadcast type network)
do not correspond, a certain transformation process for making the codecs correspond
to each other may be used. For example, if the broadcast type network for providing
BCAST service contents supports MPEG4 while the mobile communication network
(non-broadcast type visiting network) for receiving the BCAST service contents
supports MPEG2, not MPEG4, then the mobile communication network is configured
to decode the MPEG-4 contents received from the broadcast type network, encode
them to MPEG2 and then transmit the MPEG-2 contents to the user terminal. In this
case, a procedure for exchanging a contents coding method supported in the broadcast
type network and a contents coding method supported in the mobile communication
network (non-broadcasting type network) can be added before the contents are
provided, and such a procedure is known. In addition, if the home network knows ca-
pabilities (for example, a supported codec, a data rate, resolution of a screen of the
terminal) of the user's terminal, then corresponding information (e.g., terminars
capability information) can be transmitted to the visiting network so that the visiting

network can use the information to suitably transform the contents received from the
home network before transmitting it to the user's terminal.
[67] In the embodiments of Figs. 3-5, it has been described that the wish list of the
current user is used to generate the service guide to be provided to the terminal
roaming in the visiting network. However, the present invention is not limited thereto,
and encompasses a situation where the wish list of the current user is not used to
generate the service guide to the current user at the terminal. For instance, without
regards to the user's wish list, the service guide, to be provided to the end user at the
terminal 300, may be a service guide generated based on the user's subscription policy,
or can be a service guide that includes all the BCAST services offered by the home or
visiting network.
[68] Figure 6 is a signal flow chart of a BCAST service method according to another
embodiment of the present invention. In this embodiment, a BCAST service guide is
transmitted from a visiting network 200 to a terminal 300 before the terminal requests
it. That is, the visiting network, which is abroadcast type network, broadcasts its.
service guide repeatedly using its broadcasting mechanism (e.g., BDS or interaction
network) to all terminals roamed into the visiting network. Each terminal then can
request access (request right objects) to one or more BCAST services on the service
guide, and thereby accesses the BCAST service.
[69] In Fig. 6, it is assumed that the user of the current terminal 300 has a subscription to
one or more (BCAST) services offered by the home network 100 of the terminal 300
before the user roams to the visiting network 200. The home network 100 may include
a BSA unit 110, a BSM unit 120, a BSDA unit 130, and a BDS-SD unit or BDS or IN
140. The visiting network 200 may include a BSA unit 210, a BSM unit 220, a BSDA
unit 230, and a BDS-SD unit or BDS or IN 240. These components have been
discussed in connection with Fig. 1. The home network 100 and the visiting network
200 can be the same broadcast type networks or different broadcast type networks. All
the components of Fig. 6 are operatively coupled.
[70] Now, referring to Fig. 6, the terminal 300, which has roamed to the visiting network
200, receives a BCAST service guide of the visiting network 200 from the BSDA unit
230 of the visiting network, without being connected with the home network 100 (step
S81). Namely, the visiting network 200 provides its service guide to the terminal 300
which has roamed to the visiting network 200, without the user's request and without
any contact with the home network 100. This may be accomplished by the visiting
network 200 by repeatedly broadcasting its service to all terminals that roamed into the
visiting network 200, e.g., using its broadcasting mechanism.
[71] Upon checking the service guide, the user requests a use privilege (access in-
formation, e.g., right object(s) RO) in order to access a specific BCAST service

identified in the service guide from the BSM unit 220 of the visiting network (step
S83). The use privilege is a right with respect to contents requested by the user or a
right for accessing or using the BCAST service. The BSM unit 220 of the visiting
network receives this request and also checks the service authentication of the cor-
responding terminal 300 from the BSM unit 120 of the home network. Namely, the
BSM unit 220 of the visiting network transmits a service authentication request
message to the BSM unit 120 of the home network (step S85), and the BSM unit 120
of the home network checks the service authentication of the terminal and transmits a
service authentication response message to the BSM unit 220 of the visiting network
(step S87). The service authentication response message includes the result of the
service authentication. The service authentication may involve detenriining whether or
not the current terminal 300 is a subscriber of the home network 100, and examining in
detail the subscription policy of ths user of the terminal 300 so as to determine whether
or not the user should receive the specific BCAST service requested by the user at step
S81. The actual service authentication can be performed by the home network 100, or
the visiting network, or in part by the home network and in part by the visiting
network.
[72] If the service authentication result indicates that the terminal 300 is authorized to
receive the BCAST service, the BSM unit 220 of the visiting network transmits the use
privilege (access information such as RO) for allowing access and/or use of the
specific BCAST service requested by the user, to the user (step S89). RO can be a key
or code to open or decrypt the BCAST service (contents). The BSDA unit 230 of the
visiting network transmits the user-requested contents (BCAST service) to the terminal
300 through its broadcasting mechanism (step S91). In this case, the BSDA unit 230
and the BSM unit 220 may transmit or exchange information and signals through
internal communication.
[73] Upon receiving the contents, the terminal 300 accesses or interprets the received
contents by using the RO. The BSM unit 220 of the visiting network generates
charging (billing) information (e.g., charges regarding the use of the contents, etc.)
according to the use of the corresponding contents (S93), and the visiting network 200
can send the generated charging information to the home network 100 so that the user
can be billed appropriately by the home network. The visiting network 200 sends the
charging information to the home network 100 for the services the visiting network
provided since the user has a subscription contract with the home network 100. The
charging information may include any other service fee of the visiting network 200 for
allowing the roaming user to receive a BCAST service.
[74] According to the present invention, the step of generating the charging information
in step S93 may also be performed in other embodiments, e.g., in the embodiments of

Figs. 3-5. For instance, if the visiting network merely passes on the BCAST service
contents provided by the home network, the charging information may include any
service fee of the visiting network 200 for merely passing on the BCAST service
contents.
[75] As so far described, the broadest/multicast service system and method for
supporting inter-network roaming in accordance with the embodiments of the present
invention have many advantages.
[76] For example, after the terminal roams into a visiting network, it can now receive the
same BCAST service as the BCAST service that the terminal has received in the home
network, at a current location in the visiting network.
[77] In addition, because the user can set and receive his/her preferred BCAST service
with continuity regardless of its position (e.g., whether the user is currently located in
the home network or visiting network), the user's convenience and satisfaction for
receiving the BCAST service can be enhanced greatly.
[78] Theforegoing embodiments and advantage are merely exemplary and are not to be
construed as limiting the present invention. The present teaching can be readily applied
to other types of apparatuses or systems. The description of the preferred embodiments
of the present invention is intended to be illustrative, and not to limit the scope of the
claims. Many alternatives, modifications, and variations will be apparent to those
skilled in the art. In the claims, means-plus-function clauses are intended to cover the
structure described herein as performing the recited function and not only structural
equivalents but also equivalent structures.

WE CLAIM:
1. A method of providing a broadcast/multicast (BCAST) service when a
terminal roams from a home network to a visited network, the method comprising the
steps of:
generating, by a BCAST service distribution/adaptation (BSDA) unit of the
visited network, a BCAST service guide for the terminal based on a wish list of the
terminal, wherein said wish list of the terminal is a user's preferred BCAST services,
which can be selected by the user from a. list of all the BCAST services offered by the
user's home network or from a list of all the BCAST services that the user has
subscribed to from the user's home network;
transmitting, by the BSDA unit of the visited network, the BCAST service guide
to the terminal;
receiving, by a BCAST subscription management (BSM) unit of the visited
network, a request from the terminal to access at least one BCAST service based on the
service guide;
transmitting, by the BSM unit of the visited network, a service authorization
request to a BSM unit of the home network;
receiving, by the BSM unit of the visited network, a service authorization
response from the BSM unit of the home network in response to the service
aumorization request;
transmitting, by the BSM unit of the visited network to the terminal, at least one
rights object (RO) to access the at least one BCAST service, wherein the RO comprises
a key or code used to open or decrypt contents of the at least one BCAST service; and
providing, by the BSDA unit of the visited network, the at least one BCAST
service to the terminal.
2. The method as claimed in claim 1, wherein the step of transmitting the
BCAST service guide and the step of providing the at least one BCAST service are
performed via a broadcast distribution system (BDS) that cooperates with the BSDA
unit.

3. The method as claimed in claim 2, wherein the BDS supports a bearer
providing the BCAST service and supports at least one among a group of technologies
comprising DVB-H, MBMS, BCMCS, ISDB-T, and DMB.
4. The method as claimed in claim 3, wherein the BSDA unit of the visited
network provides the BCAST service guide to the terminal by repeatedly broadcasting
said BCAST service guide to terminals that roamed into the visited network without
having to receive any user request or without having to receive the same or different
BCAST service guide from the home network.
5. The method as claimed in claim 4, wherein the BCAST service guide is
provided by the BSDA unit of the visited, network and is provided independently of the
same or different BCAST service guide provided by a BSDA of the home network.
6. A visited network that provides a broadcast/multicast (BCAST) service
when a terminal roams to the visited network, the visited network comprising:
a BCAST service distribution/adaptation (BSDA) unit of the visited network,
adapted to:
generate a BCAST service guide for the terminal based on a wish list of the
terminal, wherein said wish list of the terminal is a user's preferred BCAST services,
which can be selected by the user from a list of all the BCAST services offered by the
user's home network or from a list of all the BCAST services mat the user has
subscribed to from the user's home network,
transmit the BCAST service guide to the terminal, and
provide at least one BCAST sendce to the terminal; and
a BCAST subscription management (BSM) unit adapted to:
receive a request from the terminal to access at least one BCAST service based
on the service guide,
transmitting a service authorization request to a BSM unit of a home network
of the terminal,
receive a service authorization response from the home network of the terminal
in response to the service audiorization request, and

transmit at least one rights object (RO) for accessing the at least one BCAST
service to the terminal, wherein the RO comprises a key or code used to open or decrypt
contents of the at least one BCAST service to the terminal.
7. The network as claimed in claim 6, wherein the BSDA unit cooperates with
a broadcast distribution system (BDS) in the network to provide the service guide and
provide the BCAST service.
8. The network as claimed in claim 7, wherein the BDS supports a bearer
providing the BCAST service and supports at least one among a group of technologies
comprising DVB-H, MBMS, BCMCS, ISDB-T, and DMB.
9. The network as claimed in claim 8, wherein the BSDA unit of the visited
network is adapted to provide the BCAST service guide to the terminal by repeatedly
broadcasting said BCAST service guide to terminals that roamed into the visited
network without having to receive any user request or without having to receive the
same or different BCAST service guide from the home network.
10. The network as claimed in claim 9, wherein the BCAST service guide is
provided by the BSDA unit of the visited network and is provided independendy of the
same or different BCAST service guide provided by a BSDA of the home network.

ABSTRACT

BROADCAST/MULTICAST SERVICE SYSTEM AND
METHOD PROVIDING ESTER-NETWORK ROAMING
A method and system for providing a broadcast/multicast (BCAST) service, are
provided to guarantee continuity of the BCAST service even when a user roams in the
same network or between different networks. The method involves transmitting a
BCAST service guide to terminal 300 (S81), receiving a request from the terminal 300
to access at least one BCAST service based on the service guide (S83), transmitting a
service authorization request to a BSM unit 120 of a home network 100 (S85), receiving
a service authorization response from the BSM unit 120 of the home network 100 (S87)
in response to the service authorization request, transmitting to the terminal 300 at least
one rights object (RO) to access the at least one BCAST service (S89), and providing
the at least one BCAST service to the terminal 300 (S91).

BROADCAST/MULTICAST SERVICE SYSTEM AND METHOD PROVIDING INTER-NETWORK ROAMING

Documents:

Inventors:

PCT Conventions: