KR20080057125A - Apparatus and method for transmitting/receiving data in terrestrial dmb conditional access system - Google Patents

Abstract

An apparatus and a method for transmitting/receiving data in a terrestrial DMB conditional access system are provided to load an EMM (Entitlement Management Message) of a terrestrial DMB limit receiving system in one of the service components to be scrambled and to transfer the EMM so as to reduce the overhead of the transmission bit rate. An apparatus for transmitting/receiving data comprises an insertion position selecting part(310), a qualification management message insertion part(320), and an insertion position providing part(330). The insertion position selecting part selects one service component from a transmission including a main service channel and a high speed information channel. The qualification management message insertion part inserts a qualification management message of applying or renewing a receiving qualification of a DMB service to the selected service component. The insertion position providing part inserts the position information of the selected service component in the high speed information channel.

Description

Apparatus and Method for transmitting / receiving data in terrestrial DMB conditional access system}

1A and 1B are diagrams illustrating an embodiment of a structure of a transmission frame and a transmission protocol of a terrestrial DMB used in the present invention.

2 is a view showing an embodiment of the structure of a terrestrial DMB CA system used in the present invention.

3 is a diagram illustrating a structure of a transmitter in a terrestrial DMB CA system according to an embodiment of the present invention.

4 is a diagram illustrating a data structure of fast information group (FIG) type 6 that conveys EMM location information.

5 is a diagram illustrating a flow of a transmission method in a terrestrial DMB CA system according to an embodiment of the present invention.

6 is a view showing the structure of a receiving apparatus in a terrestrial DMB CA system according to an embodiment of the present invention.

7 is a diagram illustrating a flow of a receiving method in a terrestrial DMB CA system according to an embodiment of the present invention.

8 is a flowchart illustrating a method of extracting and processing an ECM and an EMM in a receiving apparatus in a terrestrial DMB CA system according to an embodiment of the present invention.

The present invention relates to a transmission and reception apparatus and method used in a conditional access system for granting limited rights for terrestrial DMB service, and more particularly, to efficiently transmit and receive an EMM in a terrestrial DMB conditional access system. The present invention relates to a receiver and a method for reducing the overhead of a bit amount.

A conditional access system is a system in which an original broadcast signal is modified and transmitted so that only a receiver having a receiving authority with respect to a corresponding broadcast program is normally viewed. Such modification of the form of the original broadcast signal so that it cannot be viewed by an unauthorized receiver is called scramble, and a key used for scramble is called a control word.

Originally, terrestrial DMB CA was listed in Chapter 9 of ETSI EN 300 401 V1.3.3, which is a terrestrial DMB transmission standard, but it is complicated to implement according to this standard and is not supported at MOT (Multimedia Object Transfer) level. Due to its shortcomings, a new separate standard, ETSI TS 102 367 V1.2.1, has been enacted. The new CA standard is not compatible with the existing CA standard, nor is it compatible with ETSI EN 300 401 V1.3.3 and with ETSI EN 300 401 V1.4.1 revised in June 2006.

According to the terrestrial DMB CA standard (ETSI TS 102 367 V1.2.1), to transmit an internal CA message, one ensemble transmits each service component to be scrambled. ECM that includes the control word corresponding to the scramble key is appropriate to transmit each service component to be scrambled, but if the EMM is repeatedly transmitted to several service components, the overhead of the transmission bit amount increases. In addition, if the EMM is loaded on only one service component and not transmitted for each service component to be scrambled, normal service cannot be provided because the EMM cannot be received when the service component is not loaded.

EMM can be loaded on the high speed information group (FIG) type 6 or subchannel 63 (transfer without payload) and transmitted on each service component to be scrambled without duplication. There is a method of transmitting the EMM dedicated subchannel location in the CA field of the CC group 6, both of which are the new terrestrial DMB CA standard, ETSI TS 102 367 V1. There is a problem of not complying with 2.1.

The technical problem to be achieved by the present invention is to comply with the terrestrial DMB limited reception standard, so that the EMM can be transmitted without being duplicated for each scrambled service component, so that the overhead of the terrestrial DMX limited reception system with a low overhead of the transmission bit amount according to the limited reception service is provided. To provide a transceiver and a method.

In order to achieve the above technical problem, according to an embodiment of the present invention, a transmission apparatus in a CA system is configured to control a main service channel and a main service channel including subchannels including at least one service component. Insertion position selection unit for selecting one service component in a transmission frame including a high-speed information channel (FIC) for transmitting information, the qualification to insert a credential management message for granting or updating the receiving authority of the DMB service to the selected service component A management message insertion unit, and an insertion position providing unit for loading position information of the selected service component on the high speed information channel.

In order to achieve the above technical problem, according to an embodiment of the present invention, a method of transmitting in a CA system is provided. (A) a main service channel and a main service channel including subchannels including at least one service component; Selecting one service component in a transmission frame including a high-speed information channel through which control information is transmitted, and (b) inserting a credential management message for granting or updating a receiving right of a DMB service to the selected service component. (c) loading location information of the selected service component on the high speed information channel.

In accordance with one aspect of the present invention, there is provided a method of receiving in a CA system, the method comprising: (a) a main service channel (MSC) consisting of subchannels including at least one service component and the Receiving a receiving frame including a fast information channel (FIC) for transmitting control information on a primary service channel, (b) an entitlement management message (EMM) for granting or updating the right to receive a DMB service from the fast information channel; Acquiring the embedded location information), and (c) extracting the credential management message from the main service channel using the acquired location information.

Hereinafter, with reference to the accompanying drawings will be described in detail a transmission and reception apparatus and method in a conditional access system according to the present invention.

1A and 1B are diagrams illustrating an embodiment of a structure of a transmission frame and a transmission protocol of a terrestrial DMB.

Referring to FIG. 1A, a transmission frame (ensemble frame) of a terrestrial DMB is composed of a synchronization channel 110, a fast information channel (FIC) 120, and a main service channel (MSC) 130. have.

The sync channel 110 includes information for synchronizing each transport frame.

The FIC 120 includes multiplexing configuration information, service information, and the like so that the receiver can access the information quickly. In addition, the FIC 120 is composed of a plurality of fast information blocks (FIBs), and the FIB is composed of a plurality of fast information groups (FIGs). Signaling of parameters or CAs for CA services, such as whether CA is applied or not, CA mode is mainly transmitted through the FIC 120 rather than the MSC 130. Among the FIC 120, the fast information group (FIG) type 6 is used for the purpose of transmitting parameters related to CA, for example, the version of CA, the algorithm applied, and the system being used for CA. It delivers CAIntChar: CA System Internal Characteristics such as regulatory parameters, channel ID, and length information.

The MSC 130 is composed of several subchannels, each subchannel including one or more service components. The MSC 130 delivers the DMB content corresponding to the payload and the internal CA. CA internal messages are EMM and ECM.

The broadcast data of the terrestrial DMB is hierarchically multiplexed according to the characteristics of the service component, and is finally multiplexed and transmitted in one ensemble frame format. In the CA standard, one of three CA modes, subchannel mode, data group mode, and multimedia object transfer (MOT) mode, may be applied according to the hierarchy and characteristics of the corresponding service component. It is supposed to be.

Referring to FIG. 1B, the subchannel mode indicates scrambling the entire subchannel of the MSC 130. That is, the audio subchannel 131 including the PAD 135, the packet mode subchannel 132, and the stream mode subchannel 133 are subject to scramble.

Data group mode refers to scrambled MSC data group 140 transmitted over packet mode subchannel 132 or PAD 135. Data transmitted through the MOT directory mode 141, the MOT header mode 142, the IP tunneling 143, and the transparent data channel 144 are subject to scramble.

The multimedia object transfer (MOT) mode refers to scramble some or all of the objects in the MOT directory mode 141 structure.

2 is a view showing an embodiment of the structure of a terrestrial DMB CA system used in the present invention.

Referring to FIG. 2, the transmitter of the terrestrial DMB CA system includes a CA message encoder 210, a control word generator 220, a synchronizer 230, a scrambler 240, and an ensemble multiplexer 250. The receiver includes a demultiplexer 260, a conditional message decoder 270, a synchronizer 280, and a descrambler 290.

The conditional message encoder 210 generates an ECM and an EMM.

An Entitlement Control Message (ECM) encrypts a control word and transmits it to the receiver. The entitlement control message (ECM) is periodically transmitted for safety, and a new control word is encrypted each time.

An Entitlement Management Message (EMM) serves to entitle or renew a receiver.

The message generated by the CA message encoder 210 is called CA System Internal Message (CAIntMessage).

The control word generator 220 generates a control word, which is a key used when scrambled content, and transmits the control word to the synchronizer 230.

The synchronizer 230 synchronizes the scramble and the control word transfer process. The control word generated by the control word generator 220 is transmitted to the scrambler 240 and the conditional message encoder 210 through the synchronizer 230. In addition, CA Synchronization Parameter (CASyncParam) is generated to allow the receiver to synchronize the process of decoding the message and descramble the content. The toggle signal for changing the control word in the CASyncParam is an essential parameter.

The scrambler 240 mixes and transforms the content by using the control word generated by the control word generator 220 as a key so that an unauthorized receiver cannot access the content.

The multiplexer 250 multiplexes the content scrambled by the scrambler 240 and the internal reception message generated by the CA 210 and the synchronization parameter generated by the synchronizer 230 to form a single ensemble frame. .

The demultiplexer 260 demultiplexes one ensemble frame into scrambled content, CA internal messages, and synchronization parameters.

The conditional message decoder 270 interprets the message received from the conditional access system received from the demultiplexer 260 to start a corresponding process of qualification management, qualification check, and control word processing.

The synchronizer 280 interprets the conditional access synchronization parameter from the demultiplexer 260 and synchronizes the control word to the descrambler.

The descrambler 290 descrambles the scrambled content received from the demultiplexer 260 using the control word received from the CA message decoder 270.

3 is a diagram illustrating a structure of a transmitter in a terrestrial DMB CA system according to an embodiment of the present invention.

Referring to FIG. 3, as a preferred embodiment of the present invention, the transmission apparatus includes an insertion position selection unit 310, a qualification management message insertion unit 320, and an insertion position providing unit 330. Through this configuration, the transmitter inserts and transmits the EMM and the EMM location information in the transmission frame.

The insertion position selector 310 selects one service component into which the EMM is to be inserted from among at least one or more service components included in the MSC 130 (see FIG. 1) of the transmission frame. This is to reduce the overhead of the transmission bit amount due to redundant transmission of the EMM by inserting the EMM into only one selected service component, unlike the ECM and CASyncParam, which are separately inserted for every service component included in the MSC 130.

As a service component to insert an EMM, a service component with a high frequency of use is selected. This is to increase the efficiency of the terminal. If the EMM is transmitted to a service component with a low frequency of use, the terminal effectively processes the service component and the service component in which the EMM is loaded, that is, two service components have to be processed at the same time. That is, it is disadvantageous in terms of power consumption and the like.

For example, the usage frequency may be measured based on the number of paid subscribers when paid for each service component, and may be measured by a viewership survey.

The entitlement management message insertion unit 320 inserts the EMM into one service component selected by the insertion position selection unit 310. The method of inserting the EMM into the selected service component varies depending on the range in which the selected service component is scrambled, that is, the CA mode of the selected service component.

If the selected service component is scrambled to the subchannel mode (CAMode is "000"), that is, if the limited reception mode of the selected service component is the subchannel mode, the reception prefix of the subchannel to which the selected service component belongs (SUB-channel). Insert the EMM in the Conditional Access Prefix: SUBCAPrefix) field.

SUBCAPrefix is a header field of a subchannel located in front of scrambled content, and is used to deliver a conditional access message.

MSC data group if the selected service component is scrambled to data group mode (CAMode is "001") or MOT mode (CAMode is "010"), that is, if the conditional access mode of the selected service component is data group mode or MOT mode. Insert an EMM into the data field.

If the EMM is not loaded in a specific position and is not transmitted, an EMM is separately inserted for each service component included in the MSC 130.

The insertion position providing unit 330 carries predetermined information indicating the position of the service component in which the EMM is inserted in the FIC 120 of the transmission frame.

The insertion location providing unit 330 uses the CAIntChar field in the fast information group (FIG) type 6 as a location for delivering the EMM location information. The CAIntChar field conveys CA internal characteristics such as the version of CA system used for CA service, applied algorithm, system specification parameter, channel ID, and length information.

4 is a diagram illustrating a data structure of fast information group (FIG) type 6 that conveys EMM location information. FIG. 4A shows the FIG. 6 data structure when the CA component of the service component is in the sub-channel mode, and FIG. 4B is a FIG. 6 data when the CA mode of the service component is the data group mode or the MOT mode. 4C shows a data structure of the fast information group (FIG) type 6 in the case where the EMM is not transmitted in a specific position.

Referring to FIG. 4A, when a service component on which an EMM is loaded is scrambled in a subchannel mode (CAMode 420 is “000”), a subchannel identifier (SubChId: Sub-Channel Identifier, 410) is transmitted as EMM location information. do.

Referring to FIG. 4B, when the data is scrambled in the data group mode (CAMode 420 is "001") or in the MOT mode (CAMode 420 is "010"), the SubChId 410 and the service component are used as EMM location information. It delivers an identifier (SCId: Service Component Identifier) 430.

Referring to FIG. 4C, even when the EMM is not loaded in a specific position and transmitted, a value indicating a state in which the one service component is not selected so that the receiving device knows it is transmitted (for example, “11111111”). do.

5 is a diagram illustrating a flow of a transmission method in a terrestrial DMB CA system according to an embodiment of the present invention.

Referring to FIG. 5, the transmission method according to the present embodiment includes the steps of time-series processing in the transmission apparatus illustrated in FIG. 3. Therefore, even if omitted below, the contents described above with respect to the transmitter shown in FIG. 3 also apply to the transmission method according to the present embodiment.

First, one service component is selected from one or more service components inserted into the MSC 130 of the transmission frame (S510). As one component into which the EMM is to be inserted, a service component having a high frequency of use is selected to increase the efficiency of the terminal.

Thereafter, the EMM is inserted into the service component selected in step S510 (S520). The method of inserting an EMM into the selected service component uses a method of inserting into the SUBCAPrefix field of the subchannel to which the service component belongs or inserting into the MSC data group data field according to the scrambled range of the selected service component, that is, the receiving component's CA mode. do. If the EMM is not carried in a specific location and is not transmitted, an EMM is separately inserted for each service component included in the MSC 130.

 The location information of the service component selected in step S510 is loaded on the FIC 120 (see FIG. 1) of the transmission frame (S530). The FIC 120 uses the CAIntChar field in the fast information group (FIG) type 6 as a location for transmitting the EMM location information. The EMM location information becomes a subchannel identifier, a subchannel identifier, and a service component identifier according to the limited reception mode of the service component.

6 is a view showing the structure of a receiving apparatus in a terrestrial DMB CA system according to an embodiment of the present invention.

Referring to FIG. 6, as a preferred embodiment of the present invention, the receiving apparatus includes an EMM location acquisition unit 610 and an EMM extraction unit 620. Through this configuration, the receiving apparatus extracts the EMM from the receiving frame and is entitled to receive the service component through the receiving frame, thereby allowing the scrambled service component to be viewed.

The EMM position acquisition unit 610 obtains the position information into which the EMM is inserted from the FIC 120 (refer to FIG. 1) of the reception frame. The FIC 120 uses the CAIntChar field in the fast information group (FIG) type 6 as the location where the EMM location information is loaded. The receiver receives CA internal characteristics such as version of CA system, applied algorithm, system specification parameter, channel ID, and length information through CAIntChar field.

Among the EMM location information acquired from the CAIntChar field of the fast information group (FIG) type 6, when the CA mode (420) of the service component indicated by the EMM location information is the subchannel mode ("000"), The identifier SubChId 410 is extracted. If the CA mode (CAMode) 420 of the service component indicated by the EMM location information is the data group mode ("001") or the MOT mode ("010"), the identifier (SubChId, 410) for the subchannel and the service component. Extract the identifier (SCId, 430) for.

The EMM extractor 620 extracts the EMM from the MSC 130 (refer to FIG. 1) of the reception frame using the location information acquired by the EMM location acquirer 610. If the CA mode (CAMode) 420 of the service component indicated by the EMM location information is the subchannel mode ("000"), the EMM is extracted from the SUBCAPrefix field of the subchannel indicated by the identifier (SubChId, 410) of the extracted subchannel. do. If the CA mode (CAMode) 420 of the service component indicated by the EMM location information is the data group mode ("001") or the MOT mode ("010"), the identifier (SubChId, 410) for the subchannel and the service component. The EMM is extracted from the MSC data group data field of the service component indicated by the identifier SCId 430.

The EMM extractor 620 is included in the MSC when the location information acquired by the EMM location acquirer 610 is a value indicating a state in which the EMM is not inserted into only one service component (for example, “11111111”). Extract the EMM from each of the service components.

7 is a diagram illustrating a flow of a receiving method in a terrestrial DMB CA system according to an embodiment of the present invention.

Referring to FIG. 7, the receiving method according to the present exemplary embodiment includes steps of time-series processing in the receiving apparatus illustrated in FIG. 6. Therefore, even if omitted below, the contents described above with respect to the receiver shown in FIG. 6 also apply to the reception method according to the present embodiment.

First, a reception frame including the MSC and the FIC is received (S700).

The location information of the service component in which the EMM is inserted is obtained from the FIC 120 (refer to FIG. 1) of the received frame received in S700 (S710). The FIC 120 uses the CAIntChar field in the fast information group (FIG) type 6 as the position where the EMM location information is inserted. Extract the identifier (SubChId, 410) for the subchannel from the EMM position information acquired from the FIGIn type 6 CAIntChar field according to the CA mode (420) of the service component indicated by the EMM position information, or the identifier for the subchannel. (SubChId, 410) and an identifier (SCId, 430) for the service component are extracted.

Thereafter, the EMM is extracted from the MSC 130 (refer to FIG. 1) of the reception frame using the location information of the service component obtained in step S710 (S720). Extract the EMM from the SUBCAPrefix field of the subchannel indicated by the subchannel identifier (SubChId, 410) extracted according to the CAC 420 of the service component indicated by the EMM location information, or extract the subchannel identifier (SubChId, 410) and The EMM is extracted from the MSC data group data field of the service component indicated by the service component identifier (SCId) 430.

If the location information obtained in step S710 is a value indicating a state in which the EMM is not inserted into only one service component, the EMM is extracted from each service component included in the MSC.

8 is a flowchart illustrating a method of extracting and processing an ECM and an EMM in a receiving apparatus of a terrestrial DMB CA system according to an embodiment of the present invention.

Referring to FIG. 8, first, a frame including an MSC and an FIC is received (S800).

The CAIntChar field of the fast information group (FIG) type 6 of the received frame determines whether there is location information of the EMM (S810).

If the CAIntChar field does not exist or there is no information on the specific location where the EMM is loaded, the ECM and the EMM included in the service component to be received are extracted (S820).

If the CAIntChar field has information on a specific location on which the EMM is loaded, the information on the specific location on which the EMM is loaded is stored in a buffer (S830).

Then, the EMM contained in the specific location is extracted and stored in the buffer if the same EMM is not present in the buffer (S840).

The ECM is extracted from the service component desired to be received, and the decoded service component is descrambled to be normally watched by using the EMM stored in the buffer together with the extracted ECM (S850).

The invention can also be embodied as computer readable code on a computer readable recording medium. Computer-readable recording media include all kinds of recording devices that store data that can be read by a computer system. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disks, optical data storage devices, and the like, which are also implemented in the form of carrier waves (for example, transmission over the Internet). Include. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. In addition, functional programs, codes, and code segments for implementing the present invention can be easily inferred by programmers in the art to which the present invention belongs.

Such a method and apparatus of the present invention have been described with reference to the embodiments shown in the drawings for clarity, but these are merely exemplary, and various modifications and equivalent other embodiments are possible to those skilled in the art. Will understand. Therefore, the true technical protection scope of the present invention will be defined by the appended claims.

The present invention as described above reduces the overhead of the transmission bit amount according to the limited reception service because the EMM of the terrestrial DMB CA system is loaded on only one of the service components to be scrambled and not transmitted for each service component to be scrambled.

Claims (22)

A transmitting apparatus in a limited reception system for granting limited reception rights for terrestrial DMB services, An insertion position selection unit for selecting one service component in a transmission frame including a main service channel including sub-channels including at least one service component and a fast information channel for transmitting control information about the main service channel; A credential management message inserting unit for inserting a credential management message for granting or updating a reception right of a DMB service to the selected service component; An insertion position providing unit for loading position information of the selected service component on the high speed information channel; Transmitter comprising a. The method of claim 1, And the insertion position selector selects the one service component based on the frequency of use of the service components included in the main service channel. The method of claim 2, And wherein the frequency of use is calculated based on at least one of the number of subscribers and the viewer ratings of service components included in the main service channel. The method of claim 1, And the credential management message insertion unit inserts the credential management message in accordance with a limited reception mode indicating a range for restricting a reception right of the selected service component. The method of claim 4, wherein If the limited reception mode is a subchannel mode, The credential management message inserting unit inserts a credential management message into a restricted reception prefix of a subchannel in which the selected service component is located, And the insertion position providing unit loads the identifier for the subchannel and the limited reception mode on the high speed information channel. The method of claim 4, wherein If the conditional access mode is a data group mode, The credential management message insertion unit inserts a credential management message into a main service channel data group data field of the selected service component. And the insertion position providing unit loads the identifier for the subchannel in which the selected service component is located, the conditional access mode and the identifier for the selected service component in the fast information channel. The method of claim 4, wherein If the limited reception mode is a multimedia object transmission mode, The credential management message insertion unit inserts a credential management message into a main service channel data group data field of the selected service component. And the insertion position providing unit loads the identifier for the subchannel in which the selected service component is located, the conditional access mode and the identifier for the selected service component in the fast information channel. The method of claim 1, If the service component is not selected, The credential management message inserting unit inserts the credential management message into each service component included in the main service channel, And the insertion position providing unit loads a value indicating a state in which the one service component is not selected on the high speed information channel. In a transmission method in a conditional access system that grants limited reception rights for terrestrial DMB service, (a) selecting one service component from a transmission frame including a main service channel including a sub-channel including at least one service component and a fast information channel (FIC) through which control information for the main service channel is transmitted; step; (b) inserting a credential management message which grants or updates a receiving right of a DMB service to the selected service component; (c) loading location information of the selected service component on the high speed information channel. The method of claim 9, The step (a) is characterized in that for selecting the one service component based on the frequency of use of the service components included in the main service channel. The method of claim 10, Wherein the frequency of use is calculated based on either the number of subscribers or the viewer rating of the service component. The method of claim 9, And the step (b) inserts the credential management message according to a limited reception mode indicating a range for restricting a reception right of the selected service component. The method of claim 12, If the limited reception mode is a subchannel mode, In step (b), the credential management message is inserted into the CA reception prefix of the sub-channel in which the selected service component is located. In the step (c), placing the identifier for the sub-channel and the limited reception mode on the fast information channel. The method of claim 12, If the conditional access mode is a data group mode, Step (b) inserts the entitlement management message into the main service channel data group data field of the selected service component. And the step (c) includes an identifier for the subchannel in which the selected service component is located, the conditional access mode and the identifier for the selected service component in the high speed information channel. The method of claim 12, If the limited reception mode is a multimedia object transmission mode, Step (b) inserts the entitlement management message into the main service channel data group data field of the selected service component. The step (c) is characterized in that the high-speed information channel is loaded with an identifier for the subchannel in which the selected service component is located, the conditional access mode and the identifier for the selected service component. The method of claim 9, If the one service component is not selected, Step (b) inserts the credential management message into each of one or more service components included in the main service channel, In the step (c), a value indicating a state in which the one service component is not selected is loaded on the high speed information channel. In a receiving method in a conditional access system that grants limited receiving rights for terrestrial DMB service, (a) receiving a receiving frame including a main service channel consisting of subchannels including at least one service component and a fast information channel for transmitting control information for the main service channel; (b) obtaining location information into which a credential management message for granting or updating a DMB service is inserted from the fast information channel; and (c) extracting the credential management message from the main service channel by using the obtained location information. The method of claim 17, In the step (a), the receiving method comprises extracting the location of the service component according to the limited reception mode indicating a range for restricting the receiving authority of the service component into which the entitlement management message is inserted from the obtained location information. . The method of claim 18, If the limited reception mode is a subchannel mode, Step (b) extracts an identifier for a subchannel from the obtained location information, In the step (c), the credential management message is extracted from the limited reception prefix of the subchannel indicated by the extracted subchannel identifier. The method of claim 18, If the conditional access mode is a data group mode, Step (b) extracts the identifier for the subchannel and the identifier for the service component from the obtained location information, The step (c) is characterized in that the credential management message is extracted from the main service channel data group data field of the service component indicated by the extracted subchannel identifier and the extracted service component identifier. The method of claim 18, If the limited reception mode is a multimedia object transmission mode, In the step (b), if the limited reception mode of the service component is the multimedia object transmission mode among the obtained location information, the identifier of the subchannel and the identifier of the service component are extracted from the location information. The step (c) is characterized in that the credential management message is extracted from a main service channel data group data field of a service component indicated by the extracted subchannel identifier and service component identifier. The method of claim 17, In step (c), if step (b) extracts a value indicating a state in which the credential management message is not inserted into one service component, credential management from each service component included in the main service channel A receiving method, comprising extracting a message.

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