Description

METHOD OF PROVIDING EMM FOR DIGITAL MOBILE

BROADCASTING

Technical Field

[1] The present invention relates to a method of providing an Entitlement Management

Message (EMM) for digital mobile broadcasting, and more particularly to a method of processing an EMM transmitted through a mobile communication network when the EMM has not been normally received by a receiving terminal in a system for managing subscribers for digital mobile broadcasting.

[2]

Background Art

[3] The digital mobile broadcasting service is a broadcasting service which enables the user to view and listen various multimedia broadcasts, such as video, audio, and data, through multiple channels by using a personal portable receiving terminal or a vehicle receiving terminal, equipped with a receiving antenna, while the user is outdoors or is moving.

[4] The digital mobile broadcasting service makes it possible to provide a high quality of tone, various data service, interactivity and excellent mobile reception quality by digitizing a conventional analog-based broadcasting service, and extends the broadcasting concept from viewing and listening to viewing, listening and participating in broadcasts. In addition, the digital mobile broadcasting service makes it possible to transmit various pieces of multimedia information, such as news, traffic information, weather information, geographic position information and moving picture information in the form of text and graphicsthrough data broadcasting, in addition to music.

[5] Meanwhile, generally, since the digital mobile broadcasting service is provided for a fee, the digital mobile broadcasting service uses a conditional access system (CAS) for restricting the reception of subscribers. Such a CAS performs the reception restriction function by adjusting the viewing grade through a smart card mounted in each receiving terminal.

[6] Such technology will now be described with reference to FIG. 1. FIG. 1 is a block diagram illustrating the configuration of a conventional subscriber management system for digital mobile broadcasting service.

[7] As shown in FIG. 1, the subscriber management system includes a business information System (BIS) 10 for managing subscriber information of the digital mobile broadcasting service, a conditional access system (CAS) 20 for generating and transmitting an Entitlement Management Message (EMM) to a receiving terminal

through a broadcasting network when a change occurs in subscriber information related to a subscriber's viewing qualification and viewing grade for a charged channel, and the receiving terminal 50 for receiving a broadcast signal and the EMMtransmitted through the broadcasting network, analyzing the EMM, and displaying only a broadcasting signal corresponding to the viewing grade on a screen.

[8] Herein, the receiving terminal 50 may further include a smart card for storing the subscriber information, receiving the EMM, and then setting and changing the viewing grade.

[9] The operation of the system will now be described. First, the BIS 10 performs management, such as generation, change, and termination of information about mobile broadcasting service subscribers (i.e. information about a receiving terminal, information about a smart card, information about a mobile broadcasting subscription, and personal information of a subscriber). When anevent, such as generation, change, and termination of the subscriber information, is generated, the BIS 10 transmits a smart card serial number of a corresponding subscriber's receiving terminal 50, together with the event, to the CAS 20.

[10] The CAS 20 creates an EMM including the smart card serial number and the event, and broadcasts the created EMM to all receiving terminals 50 through the broadcasting network. That is, the CAS 20 manages the user's viewing qualification and viewing grade for a charged channel using the EMM. In this case, the EMM includes information that relates to a receiving terminal user's viewing qualification and viewing grade for the charged channel.

[11] Therefore, the receiving terminal 50 parses an EMM transmitted through the broadcasting network, and adjusts the viewing qualification and the viewing grade for the charged channel only when information obtained through the parsing is identical to key information of a smart card mounted in the receiving terminal 50.

[12] The CAS 20 broadcasts an EMM to all receiving terminals 50 of subscribers every thirty minutes. Therefore, the conventional system has a problem in that when a receiving terminal misses an EMM, for example, because the receiving terminal is located within a shadow area, the receiving terminal must wait until the next EMM is transmitted, so that the receiving terminal cannot be timely granted a changed viewing qualification and a viewing grade for charged channels.

[13]

Disclosure of Invention Technical Problem

[14] Therefore, the present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a method for providing

an Entitlement Management Message (EMM) for digital mobile broadcasting service, in which the EMM is transmitted through a mobile communication network (i.e. through Out Of Band) instead of a broadcasting network, so as to increase a transmission success rate because a transmission success rate of 100% cannot be ensured when, for example, a receiving terminal fails to receive the EMM due to exceptional situations, such as a case where the receiving terminal is powered off, or a case where the location of the receiving terminal has not been registered in a switching system.

[15]

Technical Solution

[16] In order to achieve the above-mentioned object, there is provided a method for providing an Entitlement Management Message (EMM) for digital mobile broadcasting service, the method including the steps of: transmitting, by a business information system (BIS), a message related to a change in subscriber information to a conditional access system (CAS) when the change in the subscriber information occurs; creating, by the CAS, an EMM according to a change in internal information, and transmitting the EMM to a mobile station (MS) server; transmitting, by the MS server, the EMM to a mobile communication network server of a mobile communication network in which the subscriber is registered; transmitting, by the mobile communication network server, the EMM to a receiving terminal; transmitting, by the mobile communication network server, a transmission failure message to the MS server when the receiving terminal fails to receive the EMM; transmitting, by the MS server having received the transmission failure message, the EMM to the mobile communication network server at every predetermined time interval so as to make the mobile communication network server retransmit the EMM to the receiving terminal; and transmitting, by the mobile communication network server, a transmission completion message to the MS server when the receiving terminal has received the EMM, and finishing an EMM provision procedure.

[17] Also, the method may further include a step of transmitting, by the mobile communication network server, a transmission completion message to the MS server when the receiving terminal has received the EMM.

[18] Also, the method may further include the steps of: determining, by the BIS, if the receiving terminal of the subscriber corresponds to a combined terminal capable of supporting both mobile communication service and digital mobile broadcasting service when the change in the subscriber information occurs; and transmitting information about whether the receiving terminal corresponds to the combined terminal according to a result of the determination, together with the message related to the change in the

subscriber information, to the CAS. [19] Also, the transmission failure message may include information representing a cause of the failure of the transmission to the receiving terminal. [20] Also, the predetermined time interval may be changeable based on transmission failure causes included in the transmission failure message. [21] In addition, the EMM provision procedure may be finished when the transmission failure cause is one among an unallocated number, a change in mobile communication networks, no authority for the use of a mobile communication network, and an SMS reception denial state. [22]

Advantageous Effects

[23] According to the present invention as described above, when an EMM is transmitted through a mobile communication network (i.e. Out Of Band) instead of a broadcasting network, the EMM is automatically retransmitted at every predetermined period of time when a receiving terminal fails to receive the EMM due to exceptional situations, such as when the receiving terminal is powered off, or when the location of the receiving terminal has not been registered in a switching system. Accordingly, when an EMM is generated, for example, due to a change of user information of a mobile broadcasting service subscriber, it is possible to rapidly transmit the EMM to the receiving terminal of the subscriber, and to apply the EMM to the receiving terminal.

[24]

Brief Description of the Drawings

[25] FIG. 1 is a block diagram illustrating the configuration of a conventional subscriber management system for digital mobile broadcasting service;

[26] FIG. 2 is a block diagram illustrating the configuration of a subscriber management system for digital mobile broadcasting service according to an exemplary embodiment of the present invention; and

[27] FIG. 3 is a view illustrating a part of the method of providing an EMM in the subscriber management system for digital mobile broadcasting service according to an exemplary embodiment of the present invention.

[28]

Mode for the Invention

[29] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

[30] FIG. 2 is a block diagram illustrating the configuration of a subscriber management system for digital mobile broadcasting service according to anexemplary embodiment

of the present invention. As shown in FIG. 2, the subscriber management system includes a business information System (BIS) 10, a conditional access system (CAS) 20, a mobile station (MS) server 30, at least one mobile communication network server 40, and a receiving terminal 50. The BIS 10 manages subscriber information of the digital mobile broadcasting service. The CAS 20 generates and transmits an Entitlement Management Message (EMM) to the MS server 30 when a change occurs in subscriber information. The MS server 30 receives the EMM, and transmits the EMM to the mobile communication network server 40 of a mobile communication provider corresponding to a serial number of a receiving terminal, which is included in the EMM. The mobile communication network server 40 transmits the EMM, which is received from the MS server 30, to the receiving terminal 50 through a corresponding mobile communication network. The receiving terminal 50 receives the EMM transmitted through the mobile communication network, parses the EMM, and displays a broadcast signal transmitted through a broadcasting network on a screen according to a predetermined viewing grade. In addition, the receiving terminal 50 may include a smart card (not shown) for storing subscriber information, receiving EMMs, and setting and changing a viewing grade.

[31] The BIS 10 performs management, such as generation, change, and termination of information about mobile broadcasting service subscribers (i.e. information about a receiving terminal, information about a smart card, and personal information of a subscriber). When an event, such as generation, change, and termination of the subscriber information, is generated, the BIS 10 transmits a smart card serial number of a corresponding subscriber's receiving terminal 50 and information about the receiving terminal, together with changed contents, to the CAS 20. In this case, the information about the receiving terminal may include information about a mobile communication company, and the telephone number of the receiving terminal.

[32] The CAS 20 creates an EMM including the smart card's serial number and the changed contents, and transmits the created EMM to the receiving terminal 50 through the MS server 30, the mobile communication network server 40, and the mobile communication network.

[33] That is, the CAS 20 manages the user's viewing qualification and the viewing grade for the charged channel using the EMM, wherein the EMM includes information about the receiving terminal user's channel viewing qualification and viewing grade for the charged channel, and a smart card's serial number.

[34] Therefore, only a receiving terminal 50, which includes a smart card having a serial number identical to that included in the EMM, changes information about the viewing qualification and the viewing grade for the charged channel. In this case, the CAS 20 may transmit the EMM including information about whether the subscriber is

authorized, or may separately create and transmit only a message including information about whether the subscriber is authorized, and changed contents of subscriber information on behalf of the EMM.

[35] The MS server 30 acts as a message parsing server between the CAS20 and the mobile communication network server 40 for the mobile communication network. The MS server 30 inserts information to divisionally manage a session according to the respective mobile communication companies into the EMM, processes the EMM into a format that the mobile communication network server 40 can receive, andtransmits the process EMM to the mobile communication network server of each mobile communication company.

[36] The mobile communication network server 40 is built according to each mobile communication company, processes the EMM into a data format (e.g. an Over The Air (OTA) or a Short Message Service (SMS)) and a data packet) to be transmittable through the mobile communication network, if necessary, and then transmits the processed EMM to the receiving terminal.

[37] The processing of the EMM may be performed by the MS server 30 or the mobile communication network server 40.

[38] The receiving terminal 50 is a combined terminal capable of simultaneously providing the digital mobile broadcasting reception service function and the mobile communication service function. After receiving and parsing the EMM, the receiving terminal 50 stores the viewing qualification, various pieces of key information for viewing, and a viewing grade for charged channels when a smart card's serial number included in the EMM is identical to that (or information for authentication) stored in the receiving terminal 50, receives a broadcast signal through the broadcasting network, and displays the broadcast signal on a screen.

[39] FIG. 3 is a view illustrating a part of the method of providing an EMMin the subscriber management system for digital mobile broadcasting service according to an exemplary embodiment of the present invention. That is, FIG. 3 illustrates a procedure in which the MS server 30, which has received an EMM created by the CAS 20, provides the EMM to the receiving terminal 50.

[40] First, when a change occurs in subscriber information, the BIS 10 transmits a message about the change in the subscriber information to the CAS 20, and then the CAS20 creates an EMM based on the message and transmits the EMM to the MS server 30 (step 2). Next, the MS server 30 transmits the EMM to the mobile communication network server 40 of a mobile communication network, in which the subscriber has registered (step 4).

[41] Then, the mobile communication network server 40 transmits the EMM to the receiving terminal 50. In this case, when the receiving terminal 50 cannot receive the

transmitted EMM on account of an abnormal situation, that is, when the mobile communication network server 40 cannot confirm that the receiving terminal 50 has received the EMM, the mobile communication network server 40 transmits a transmission failure message, which includes information representing a cause of transmission failure, to the MS server 30 (step 6).

[42] Upon receiving the transmission failure message, the MS server 30 transmits the

EMM to the mobile communication network server 40 at every predetermined period of time based on a predetermined retransmission policy so that the mobile communication network server 40 can retransmit the EMM to the receiving terminal 50 (steps 8 and 10).

[43] Thereafter, when the EMM is normally transmitted/received between the mobile communication network server 40 and the receiving terminal 50 (step 12), the mobile communication network server 40 transmits a transmission completion message to the MS server 30 so that the retransmission procedure can be finished.

[44] Hereinafter, a policy for retransmission according to causes of transmission failure, which must be predetermined for the aforementioned procedure, will be described in more detail.

[45] When transmission of an EMM through a mobile communication network results in a failure, an MS server receives a transmission failure message as a return message. The received transmission failure message includes information about a cause of transmission failure. The MS server automatically performs a retransmission procedure according to the cause of transmission failure. When the EMM has been successfully transmitted through the retransmission, the retransmission procedure currently in progress is finished.

[46] The retransmission interval is set to a different value depending on each cause of transmission failure so as to minimize a delay in information processing through the mobile communication network. Examples of the causes of transmission failure are shown in Table 1.

[47] Table 1

[48]

[49] [50] The retransmission policy is classified into three types, and different retransmission intervals are applied, as described below.

[51] - Code 1 (Default): every 3 minutes until the 10 retransmission, and every 10 minutes from the 11 retransmission to the 20 retransmission [52] - Code 2 (Power off): every 60 minutes until the 10 retransmission, and every 360 minutes from the 11 retransmission to the 20 retransmission [53] - Code 3 (OTA Not Connected): every 10 minutes until the 10 retransmission, and every 20 minutes from the 11 retransmission to the 20 retransmission

[54] 1) Case of Power off [55] When a receiving terminal is powered off, it is impossible to transmit a message

through a mobile communication network. Therefore, in this case, an automatic retransmission procedure is performed after a transmission failure has been handled. During the retransmission interval, since the MS server having received a notification from the mobile communication network server performs a retransmission operation as soon as the receiving terminal is powered on and enters a normal state for its operation related to mobile communication, it is unnecessary to set the retransmission interval short. Therefore, the retransmission policy of Code 2 is adopted to have a long retransmission interval in such a manner as to perform retransmissions every 60 minutes until the 10 retransmission, and every 6 hours from the 11 retransmission to the 20 retransmission.

[56] The notification procedure is performed for the mobile communication network server to notify the MS server that the receiving terminal is shifted into an available state after it is reported that a previous EMMtransmission request has failed due to in- activation or the like. If the mobile communication network server has a function of managing the retransmission policy and retransmitting an EMM, the notification procedure may be omitted.

[57] Meanwhile, after receiving the notification, the MS server may resume the EMM transmission procedure or may discard the EMM without performing any operation, according to the retransmission policy.

[58] 2) Case of OTA Not Connected

[59] When a transmission fails because the mobile communication network server and the MS server are disconnected from each other due to a network operation or a circuit failure,the retransmission policy of Code 3 is applied, thereby performing retransmissions every 10 minutes until the 10 retransmission, and every 20 minutes from the 11 retransmission to the 20 retransmission.

[60] 3) Case of exceptional situations

[61] With respect to the case of exceptional situations, an unallocated number, number porting, a case where there is no authority for the use of the OTA (or SMS), and a case of an SMS reception denial state, in which EMM transmission cannot be normally processed before subscriber information of a mobile communication company is corrected, the automatic retransmission is not performed for reducing the load of the MS server.

[62] 4) Case of normal failures

[63] With respect to the case of the other transmission failures, except for the cases of the exceptional situations, the power off, and the OTA Not Connected, the retransmission policy of Code 1 is applied.

[64] 5) When a mobile identification number (MIN) is not changed, but a CAS number is changed due to terminal replacement of a subscriber, a termination message must be

transmitted to an existing receiving terminal and the termination processing must be performed before an opening message is transmitted to a new receiving terminal. If the transmission of the termination message fails because the existing receiving terminal is powered off, retransmission is automatically performed, so that there is a problem in that the opening message to be transmitted to the new receiving terminal is stored in a stack and is not processed during the twenty retransmission cycles for the failed message.

[65] Therefore, in the case of a terminal replacement, if the transmission of a termination message to the existing receiving terminal fails due to being off, the MS server stops transmitting the termination message, and transmits an opening message to the new receiving terminal so as to allow the new receiving terminalto be used.

[66] According to the method of automatically retransmitting an EMM based on the retransmission policy, when an EMM is generated by a change in the user information of a digital mobile broadcasting service subscriber, it is possible to rapidly transmit and apply the EMM to the receiving terminal of the subscriber.

[67] The embodiments described above are only illustrative, and the present invention is not limited thereto.