KR20060111250A - A conditional access system for each transmitter in digital multimedia broadcasting system and method thereof - Google Patents

Abstract

A DMB(Digital Multimedia Broadcasting) CAS(Conditional Access System) according to a transmitter and a method therefor are provided to permit differential connection for a main broadcasting network and a relay network to a general subscriber and an expansion service subscriber in a broadcasting network having an SFN(Single Frequency Network). A TII detecting unit(830) detects TII(Transmitter Identification Information) from an encrypted broadcasting signal received through an antenna(810). A matching unit(860) searches TII of a main broadcasting network corresponding to the TII detected in the TII detecting unit(830), and outputs a session key. A CW(Control Word) generating unit(870) generates a CW by using the session key outputted from the matching unit(860). A decoder(840) decodes the encrypted broadcasting signal by using the CW generated in the CW generating unit(870). A control unit(850) controls the TII detecting unit(830), the matching unit(860), the CW generating unit(870), and the decoder(840) according to a broadcasting network to which a transmitter which is judged by the TII detected in the TII detecting unit(830) belongs and whether a system subscribes to an expansion service, and decodes the encrypted broadcasting signal.

Description

Digital Multimedia Broadcasting Restriction Receiving System and Method according to Sending Station {A CONDITIONAL ACCESS SYSTEM FOR EACH TRANSMITTER IN DIGITAL MULTIMEDIA BROADCASTING SYSTEM AND METHOD THEREOF}

1 is a diagram schematically illustrating a concept of transmitting an encrypted broadcast signal in a single frequency network according to an embodiment of the present invention.

2 is a block diagram of a transmission system for transmitting an encrypted broadcast signal for a DMB limited reception system according to an embodiment of the present invention.

3 is a diagram illustrating transmission and reception of an encrypted broadcast signal between a main broadcasting station, a relay station, an authentication system, and a subscriber station according to an embodiment of the present invention.

4 is a diagram for specifically describing a DMB restricted reception service according to an embodiment of the present invention.

5 is a diagram illustrating an encrypted broadcast signal between a main broadcast network and a relay network according to an embodiment of the present invention.

6 is a diagram illustrating a transmission signal for each channel of the main broadcasting network and the relay network according to an embodiment of the present invention.

7 is a diagram exemplifying transmission station identification information and control word transmitted through a synchronization channel in a main broadcasting network transmitting station according to an embodiment of the present invention.

8 is a diagram illustrating an example of a key table for storing a session key corresponding to an identification number in a main broadcasting network transmitting station according to an embodiment of the present invention.

9 is a block diagram of a subscriber station of a DMB conditional access system according to a transmitting station according to an embodiment of the present invention.

10 is a flowchart illustrating a DMB restriction reception method according to a transmitting station in a general subscriber station according to an embodiment of the present invention.

11 is a flowchart illustrating a DMB restriction reception method according to a sending station of an extended service subscriber station according to an embodiment of the present invention.

The present invention relates to a digital multimedia broadcasting (DMB) receiving system. More specifically, in a digital broadcasting system using a single frequency network (SFN), a separate relay network other than the main broadcasting network is shaded. When constructed for a region, the present invention relates to a system and a method for distinguishing and receiving a DMB broadcast signal according to a transmitting station by distinguishing a connection between a general subscriber station and a service subscriber station.

The features of digital broadcasting are summarized as multichannel, high quality and multifunctional. In particular, due to the development of multiplexing technology, video, audio, and data can be simultaneously bundled and transmitted irrespective of their contents and sizes, and a interactive channel is possible because a return channel can be formed through a modem. . Accordingly, digital data broadcasting can overcome the limitations of existing analog broadcasting and provide a high value-added multimedia service to viewers.

In general terrestrial and satellite digital broadcasting, within a single frequency network (SFN), each transmitting station forms a main broadcasting network or a relay network, and a shaded area in which the service is not received in the main broadcasting network or the relay network occurs. A repeater or gap filler is installed for service.

For example, in satellite digital multimedia broadcasting (DMB), most areas can be received directly from satellites, but shadow areas in subways, tunnels, and buildings that cannot be received directly use a gap filler to secure a reception area. In other words, when it is not easy to receive satellite signals directly from the ground, the gap filler receives the satellite signals through the satellite receiver antenna in tunnels, underground spaces and buildings, and relays the corresponding services.

Meanwhile, a key center (KC) refers to a broadcasting station that organizes, produces, and transmits a broadcasting sequence centered on the broadcasting network organization. In Korea, there are subsidiaries such as KBS, MBC, CBS, BBS, PBC, SBS, and Far East broadcasting in radio broadcasting, and subsidiaries such as KBS, MBC and SBS in television broadcasting. Each of these is the main station.

In addition, a relay station (RC) refers to a low power auxiliary broadcast station, also called a satellite station. Typically, the relay station has a service area, i.e., a designated broadcasting area, but in the surrounding area, a radio wave is weak due to the influence of the terrain, and a difficult reception area may occur, so that a repeater is specifically installed for such an area. Such a repeater is installed at the top of a mountain, which can receive radio waves from a main broadcasting station, receives a transmitted signal using a high sensitivity receiver, amplifies it electrically, and then broadcasts the radio at a different frequency.

On the other hand, when a third party other than a broadcasting company with a business right participates in the establishment and operation of a separate broadcasting network or a relay network, the operator participating in the new network construction has a right to use a separate broadcasting network or a relay network. Operators who do not participate in shall not be able to use or selectively use the broadcasting network or the relay network. In addition, by providing a broadcasting service to a subscriber for a corresponding broadcasting network or a relay network for a fee, a payment for service provision according to the use of a network established in a shadow area should be paid.

In other words, if the main broadcasting company and the repeater service provider are different from each other, the repeater service provider incurs the cost of setting up and maintaining the broadcasting network for the shaded area, and for such costs, the repeater service provider needs to pay for the use of the relay network. . However, there is a problem that the relay network is not activated because there is no suitable countermeasure to this point regarding the use of the relay network.

SUMMARY OF THE INVENTION An object of the present invention for solving the above problems is a digital multimedia broadcasting limited reception system according to a transmitting station capable of allowing differential access to a main broadcasting network and a relay network to a general subscriber and an extended service subscriber in a broadcasting network having a single frequency network. And a method thereof.

As a means for achieving the above object, the digital broadcast limited reception system according to the present invention,

A system for receiving limited reception of digital broadcasting based on DMB system according to a transmitting station,

A sending station identification information detecting unit for detecting sending station identification information from the encrypted broadcast signal received through the antenna; A matching unit which finds transmission station identification information of a main broadcasting network corresponding to the transmission station identification information detected by the transmission station identification information detection unit and outputs a corresponding session key; A control word generation unit generating a control word using the session key output from the matching unit; A decoder that decodes the received encrypted broadcast signal using the control word generated by the control word generator; And controlling the broadcasting station identification information detecting unit, the matching unit, the control word generator, and the decoder according to whether the broadcasting network to which the transmitting station is determined by the transmitting station identification information detected by the transmitting station identification information detecting unit and whether the system is subscribed to the extended service is received. And a control unit for decoding the encrypted broadcast signal.

Here, the matching unit finds the transmission station identification information of the main broadcasting network corresponding to the transmission station identification information detected by the transmission station identification information detection unit using a matching key received from the outside.

The controller may be further configured to analyze the broadcasting station identification information detected by the broadcasting station identification information detecting unit to determine that the encrypted broadcasting signal is transmitted from the broadcasting station belonging to the main broadcasting network. The control word may be used to decode the encrypted broadcast signal.

The controller may be further configured to analyze the broadcasting station identification information detected by the broadcasting station identification information detecting unit to determine that the encrypted broadcast signal is transmitted from the broadcasting station belonging to the relay network, and the system is subscribed to the extended service. The control word is generated using the control word generated by the control word generator, characterized in that the control to decode the encrypted broadcast signal.

Digital broadcast limited reception method according to another aspect of the present invention,

As a method for receiving a digital broadcasting based on the DMB scheme by the extended service subscriber system according to the sending station,

a) detecting, by the extended service subscriber system, transmitting station identification information from an encrypted broadcast signal received from a main broadcasting station or a relay station; b) checking whether the detected transmitting station identification information is the transmitting station identification information of the main broadcasting station; c) if it is determined that the detected broadcasting station identification information is not the broadcasting station identification information of the main broadcasting station, the extended service subscriber system receiving a matching key from the outside through the DMB network or the wireless network; And d) decoding the encrypted broadcast signal using the matching key and the detected transmitting station identification information.

Wherein step d) comprises: detecting identification information of a main broadcasting station corresponding to the detected broadcasting station identification information using the matching key; Detecting a session key corresponding to the detected identification information of the main broadcasting station; Generating a control word using the detected session key; And decrypting the encrypted broadcast signal by using the generated control word.

Further, in the step b), when it is determined that the detected transmitting station identification information is the transmitting station identification information of the main broadcasting station, the extended service subscriber system uses the control word included in the encrypted broadcasting signal to transmit the encrypted broadcast signal. And decoding the signal.

Digital broadcast limited reception method according to another aspect of the present invention,

As a method for receiving a digital broadcasting based on the DMB scheme by the general service subscriber system according to the sending station,

a) the general subscriber system detecting transmitting station identification information from an encrypted broadcasting signal received from a main broadcasting station or a relay station; b) checking whether the detected transmitting station identification information is the transmitting station identification information of the main broadcasting station; And c) if it is determined that the detected broadcasting station identification information is not the broadcasting station identification information of the main broadcasting station, decoding the encrypted broadcasting signal by using the control header included in the encrypted broadcasting signal. It includes.

Hereinafter, a digital multimedia broadcasting (MDB) limited reception system and a method thereof according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

According to the embodiment of the present invention, in a terrestrial and satellite digital broadcasting system, a subscriber can use all networks by allowing two or more networks to be differentially used by a general subscriber or an extended service subscriber in a broadcasting network having a single frequency network. For example, some subscribers can use only limited networks with limited reception.

Specifically, in an embodiment of the present invention, scrambling by a control word is applied to a transport stream transmitted to a subscriber, and the transmitter identification information (TII) is used as a value for finding a decryption key of the transport stream. Reception is restricted by the sending station. Here, TII is a unique identifier assigned to the transmitting station, and the TII signal is transmitted through a synchronous channel, and may be used together with frequency information (FI) in a single frequency network (SFN).

DMB limited reception system according to an embodiment of the present invention and a method thereof, after describing a general conditional access system (CAS), will be described a difference from the embodiment of the present invention.

CA is designed to protect various multimedia data transmitted from multiple program providers to subscriber terminals, and to receive only authorized subscribers with legitimate reception authority.

The CA system is a system in which a subscriber concept is introduced into a normal broadcast so that only a subscriber with a right viewing authority can receive a specific broadcast signal or program. Let each digital broadcast receiver decide. CA system transmits the encrypted program signal at the transmitter and the entitlement given to individual or specific group of receivers, and at the receiver side, only the authorized subscriber is attached to the receiver, For example, it is a system that can receive a program by decrypting using a smart card. Here, in the embodiment of the present invention, the authentication system provides a separate decryption key instead of the smart card to the extended service subscriber.

The sender basic structure of the CA may be composed of a subscriber management system (SMS), a scrambling engine, and an encryption engine. Subscriber management system (SMS) is a system that manages information about subscribers, and a scrambling engine is a system that scrambles a receiver without legitimate receiving authority so that it cannot receive a transport stream, that is, a program. A system that encrypts.

In addition, the receiving side structure of the CAS consists of an integrated receiver / decoder (IRD), an entitlement management message (EMM) authentication unit, an entitlement control message (ECM) authentication unit, and a transport stream block. The service key in the EMM is decrypted using a customer ID key in the decryptor of the IRD to determine whether there is a receiving authority, and the control word (CW) in the ECM is determined. Decrypt and receive the program.

Accordingly, CA requires the following functions. That is, scrambling and descrambling functions to protect the original signal from unauthorized recipients of commercial services, and entitlement control functions to be interpreted only to the specific subscriber who paid the fee. And an entitlement management function are required.

Scrambling scrambles the multimedia data to be transmitted in a predetermined rule so that the scrambled data cannot be viewed by a receiver without permission to receive the signal. In general, the signal is modified using a control word (CW). In other words, scrambling modifies the original broadcast signal form so that unauthorized recipients cannot view it, which may be different depending on the broadcast program type (audio / video / data) and the signal type (analog / digital). Descrambling is performed only at a receiver which may have a control word (CW) which is a descrambling key.

 In addition, encryption protects the control word (CW) transmitted with the scrambled signal to be sent to the receiver's decryptor. The transmitter and receiver must have the same secret key. The descrambling process can be performed accurately.

Specifically, the entitlement control function encrypts the control word CW and transmits the entitlement control message ECM to the subscriber station. The entitlement control function is periodically transmitted for safety, and a new control word is encrypted each time. The ECM may include control parameters in addition to the encrypted control word (CW), and the transmitter sends the ECM to the subscriber station, and transmits the authentication parameter and the received control variable with a microprocessor in the subscriber station. Will be compared. If the result is the same, then the receiver is authenticated and decrypts the control word CW, which is a descrambling key, with a decryption key separately received by the authenticated subscriber station. This control word CW has a different value for each program and is periodically changed.

In addition, the entitlement management function is a function of entitlement or update of a subscriber station. The entitlement management system generates and encrypts an entitlement management message (EMM) in the subscriber management system, and transmits the entitlement management message to a receiver through a transport stream. At this time, the credential management message (EMM) serves to entitle or update the credential in the receiver's decryptor.

Meanwhile, the embodiment of the present invention distinguishes between broadcasting network identification and expansion service subscription of a terminal. Network Identification Function (NIF) assigns identification information to broadcasting network and relay network by using broadcasting station identification information (TII) of terrestrial DMB standard (Eureka-147 standard ETS 300.401) and efficiently according to the divided signal. Manage your network. Accordingly, embodiments of the present invention can achieve source access blocking and security at the data level by scrambling the transmitted data using the control word (CW) and encrypting using the TII.

Here, the reason for performing scrambling is to prevent the terminal that is not equipped with the network identification function from being freely used in all networks without a prior network discrimination operation. In this case, the reason for not scrambling only in the relay network is to scramble only the relay network. In this case, this is because the signal acts as an interference in the overlapping area where signals overlap with each other unlike the signal of the main broadcasting network.

In addition, the embodiment of the present invention enables the general subscriber and the extended service subscriber to receive the service within the coverage of the main broadcasting network for the general subscriber and the extended service subscriber in the broadcasting network having a single frequency network, and the extension within the coverage of the relay network. Only service subscribers can receive the service. In addition, in the coverage where the main broadcast coverage and the relay network coverage overlap, the general subscriber and the extended service subscriber may simultaneously receive the coverage. In this case, the basic premise should not be affected by the addition of the relay network for the service to the general subscribers of the main broadcasting network, there should be no reduction in the service coverage of the main broadcasting network, and the service should be provided when handoff between the main broadcasting network and the relay network. Continuity must be ensured.

Hereinafter, with reference to the drawings, a DMB restricted reception system and a method according to a sending station according to an embodiment of the present invention will be described in detail.

1 is a diagram schematically illustrating a concept of transmitting an encrypted broadcast signal in a single frequency network according to an embodiment of the present invention.

Referring to FIG. 1, when the main broadcasting network 10 or the relay network 20 forms a single frequency network, in the main broadcasting network 10, the main broadcasting station 11 provides video, audio, and data from a plurality of program providers. Receives and encrypts it, and transmits an encrypted broadcast signal by inserting identification information (TIIa) for distinguishing the main broadcasting network. At this time, the encrypted broadcast signal is transmitted from the transmission center (TC) 13 to the relay station 21 through the main broadcasting network via the DMB broadcasting station 12 having the DMB system, or directly from the main broadcasting station 11 through a dedicated line. It may be sent to the relay station 21. At this time, when transmitting the broadcast signal from the main broadcasting station 11 to the relay station 21, the main broadcasting station 11 changes TIIa to TIIb through a specific matching algorithm, and inserts TIIb into the broadcast signal instead of TIIa to transmit the broadcasting signal. 21). The TIIa at this time is given to the main broadcasting station 11 by the authentication system 230 provided to the main broadcasting station 11. In addition, the encrypted broadcast signal in the main broadcasting network 10 is transmitted to the subscriber station 14 in the main broadcasting network 10.

In the relay network 20, the relay station 21 receives an encrypted broadcast signal through a main broadcasting network or a dedicated line, and transmits it to the repeater 21 in the shaded area via the relay link, and the repeater 22 in the shaded area is in the relay network. The subscriber station 23 is transmitted.

Accordingly, in a single frequency network according to an embodiment of the present invention, the encrypted broadcast signal transmits transmission station identification information for network classification in the main broadcasting network 10 or the relay network 20, respectively, and the main broadcasting network 10 or the relay network 20. Subscriber terminals 14 and 23 therein are each decrypted and reproduced in a different manner.

On the other hand, Figure 2 is a block diagram of a transmission system for transmitting an encrypted broadcast signal for the DMB limited reception system according to an embodiment of the present invention.

Referring to FIG. 2, the DMB transmission system includes a main broadcasting system 210, a relay system 220, and an authentication system 230, and transmits an encrypted broadcast signal to the subscriber terminal 240. Hereinafter, the main broadcasting system 210 is used in the same sense as the main broadcasting station, and the relay system 220 is used in the same meaning as the relay station.

The main broadcasting station 210 generates the control word CW by generating the broadcasting station identification information TIIa corresponding to the main broadcasting station, and then scrambles the transport stream using the control word CW, and scrambles the broadcast signal. While transmitting the data, it transmits through the main broadcasting network by including the broadcasting station identification information (TIIa) and the control word (CW) of the main broadcasting station together. The main broadcasting station 210 sets the broadcasting station identification information (TIIa) of the main broadcasting station, applies the broadcasting station identification information (TIIa) to generate a control word which is a scrambling key, and also identifies the broadcasting station of the main broadcasting station 210. The information TIIa is periodically changed, and when the encryption is performed, the changed sending station identification information TIIa is periodically applied.

)에 대응되는 세션키(

)를 나타내는 키 테이블을 특정 메모리에 저장한다. 예를 들어, 주방송국(210)의 식별번호가

라면 대응되는 세션키는

이고, 이 세션키

를 사용하여 제어단어를 생성하여 스크램블에 사용한다. More specifically, the main broadcasting station 210 controls the scrambled transport stream using the session key corresponding to TIIa through a specific key table (see FIG. 8) that stores the session key corresponding to TIIa. To generate and transmit a broadcast signal including the same, that is, an Entitlement Control Message (ECM). Referring to FIG. 8, the main broadcasting station 210 may include a plurality of main broadcasting station identification numbers (

Corresponding session key (

Store the key table in the specified memory For example, the identification number of the main broadcasting station 210

If the corresponding session key

This session key

Create a control word using and use it for scramble.

Meanwhile, when the main broadcasting station 210 transmits a broadcast signal to the relay station 220, the main broadcasting station 210 changes the broadcasting station identification information TIIa of the main broadcasting station to the broadcasting station identification information TIIb of the relay station, and then transmits the broadcasting station identification information TIIb through the relay network. ) Transmits the inserted broadcast signal to the subscriber station and the repeater of the shadow area. At this time, the main broadcasting station 210 receives the TIIb from the authentication system 230 as well as the TIIa, and the authentication system 230 is changed to the TIIb by a specific matching algorithm for the TIIa. When used, it is possible to know the TIIa corresponding to the TIIb.

The relay station 220 amplifies and transmits a signal of a main broadcasting network corresponding to a single frequency network, or modulates and amplifies and transmits a stream inputted through a dedicated line from the main broadcasting station 210. The relay network server (not shown) in the relay station 220 collects the transmission signals of six operators, generates TII, and modulates them in a time division (TDM) manner to broadcast them through a satellite earth station. Can be.

The authentication system 230 generates TIIa and TIIb and provides them to the main broadcasting station 210, and further provides a matching key for knowing TIIa, which is the identifier of the main broadcasting station 210, from TIIb, which is an identifier in the relay network. To send. At this time, the matching key may be periodically updated by the main broadcasting station 210.

Specifically, the main broadcasting station 210 includes a service multiplexer 212, a scrambler 213, a transmitter identification information (TIIa) generator 215, an encoder 214, a system multiplexer 216, a modulator 217, and May include a transmitter 218.

The service multiplexer 212 multiplexes audio, video, data and side information provided from a plurality of content providers, respectively, into a transport stream. Audio, video and data may be provided from a plurality of content providers through a video encoder 211a, an audio encoder 211b and a data server 211c, respectively. Here, the audio service is transmitted through an independent channel to provide an audio service of CD quality sound. The data service may be used to transmit text data such as song lyrics of an audio service. Since video services must contain video, audio, and multiplexing / synchronization information by themselves, they are transmitted after being created as a stream through the video multiplexer. At this time, the audio, data, and video services are multiplexed into the service channel in the service multiplexer 212, and are then bundled into one frame with the transmission data by the system multiplexer 216 and transmitted through the physical channel.

The scrambler 212 scrambles the multiplexed transport streams using a control word (CW) so that the transport stream to be transmitted is shuffled by a certain rule so that a receiver without proper receiving authority cannot receive the transport stream.

The transmitting station identification information (TIIa) generator 215 generates the transmitting station identification information (TIIa) of the main broadcasting station indicating that the transmitting station transmitting the broadcasting signal is the main broadcasting station. At this time, the sending station identification information (TIIa) generator 215 may directly generate TIIa, but preferably, TIIa generated from the authentication system 230 is received and used. The generated sending station identification information TIIa is used to generate the control word CW.

The encryptor 214 encrypts the broadcast signal output from the scrambler 212 and generates an encrypted broadcast signal including the control word CW and the transmitting station identification information TIIa.

The system multiplexer 216 multiplexes the encrypted broadcast signal together with the system control data into one ensemble transport stream. The system multiplexer 216 is also called an ensemble multiplexer, where multiple audio compression streams and different types of data are each channel-coded and then multiplexed into a single transport stream with system control data. Is called an ensemble.

The modulator 217 modulates the ensemble multiplexed broadcast signal into a transmission signal.

The transmitter 218 transmits an encrypted broadcast signal including a main broadcasting station transmitting station identification information (TIIa) and a control word (CW) to a subscriber through a main broadcasting network, or transmits a broadcasting signal including the relay network transmitting station identification information (TIIb) to a relay station ( 220).

In addition, the relay station 220 is a source identification information (GF TIIb) generator of the transmitter identification information (TIIb) inserter 221, the multiplexer / modulator 222, the relay station transmitter 223, and the Gap Filler (GF). 224, GF multiplexer / modulator 225, and GF transmitter 226.

The transmitting station identification information (TIIb) inserter 221 of the relay station analyzes the transmitting station identification information (TIIb) in the encrypted broadcasting signal received from the main broadcasting station 210 to indicate that the transmitting station transmitting the broadcasting signal is a relay station through the relay network. The broadcasting station identification information (TIIb) is inserted into the broadcasting signal transmitted to the subscriber.

The multiplexer / modulator 222 multiplexes and modulates the signal output from the transmitting station identification inserter 221 of the relay station. Here, the multiplexer / modulator 222 may be installed separately from the multiplexer and modulator.

The relay station transmitter 223 transmits the multiplexed and modulated broadcast signal to the subscriber station or transmits the multiplexed and modulated broadcast signal to the repeater (GF) in the shadow area.

The sending station identification information (GF TIIb) generator 224 of the shadow area repeater (GF) generates the sending station identification information (GF TIIb) of the shadow area repeater (GF).

The GF multiplexer / modulator 225 changes the transmitting station identification information TIIb in the encrypted broadcast signal received from the relay station to the transmitting station identification information GF TIIb of the shadow area repeater GF, and multiplexes and modulates them.

The GF transmitter 226 transmits the multiplexed and modulated broadcast signal to the subscriber station in the shadow area.

Meanwhile, the authentication system 230 includes a user authentication server 231, and the user authentication server 231 periodically transmits a matching key to extract a corresponding control word by decrypting a received key. In other words, when the extended service subscriber station has a wireless modem, the user authentication server 231 transmits a matching key to the extended service subscriber station through a wireless network, or when the extended service subscriber station does not have a wireless modem. In addition, the matching key is transmitted to the extended service subscriber station through a digital multimedia broadcasting (DMB) network.

In addition, the subscriber station 240 may be a general subscriber or an extended service subscriber, and within the main broadcasting network, the general subscriber or the extended service subscriber may watch the broadcast regardless of the encryption or not, but may subscribe to the service within the relay only. Only the extended service subscriber will watch the broadcast using the matching key transmitted from the authentication system 230. The configuration and operation of the subscriber station 240 according to an embodiment of the present invention will be described later with reference to FIG. 9.

In the embodiment of the present invention, in the case of a single frequency network, the data of the main broadcasting network and the relay network relaying the same are configured in the same stream and ensure signal synchronization, thereby configuring the broadcasting network without interference between the main broadcasting network and the relay network. Here, TII is used as sending station identification information. In practice, the TII enables the subscriber station to distinguish whether a broadcast signal is transmitted through the main broadcasting network or the relay network. In this case, the TII information does not cause interference of a single frequency network even though having different transmitting station identification information. The TII does not exist in the data domain and is usually set to a combination of carriers of an OFDM synchronization channel. By combining the combinations without overlapping, it is possible to distinguish the ID of a transmitting station even if two or more signals are received in a single frequency network. have.

3 is a diagram illustrating transmission and reception of an encrypted broadcast signal between a main broadcasting station, a relay station, an authentication system, and a subscriber station according to an embodiment of the present invention.

Referring to FIG. 3, in the main broadcasting network, when the main broadcasting station 210 transmits the broadcasting station identification information (TIIa), the control word (CW), and the encrypted broadcasting signal of the main broadcasting station to the subscriber station 240a, the subscriber station 240a. The general subscriber station or the extended service subscriber station can decode and reproduce the encrypted broadcast signal by using the transmission station identification information (TIIa) and the control word (CW) of the main broadcasting station. In addition, the main broadcasting station 210 transmits the main broadcasting station identification information TIIa to the authentication system 230 through the synchronization channel, the relay station identification information TIIb to the relay station 220, and sends the high speed information channel FIC. It sends a credential control message (ECM) / credential management message (EMM).

In the relay network, when the relay station 220 inserts the transmitting station identification information (TIIb) of the relay station into the broadcast signal and transmits it to the subscriber station 240b, when the subscriber station 240b is a general subscriber station, only the TIIb decodes the encrypted broadcast signal. However, in the case of the extended service subscriber station, it is possible to know the TIIa corresponding to the TIIb by receiving the matching key from the authentication system 230, and obtain the session key for generating the control word through the encryption system. It can be decoded and reproduced. That is, in the relay network, the relay station 220 transmits the transmitting station identification information (TIIb) and the encryption broadcast signal of the relay station to the subscriber station 240b, and sends the ECM / EMM to the authentication system 230. At this time, the matching key is received through the corresponding wireless network when the extended service subscriber station is provided with a wireless modem, and received through the DMB network to decode the encrypted broadcast signal.

4 is a diagram for specifically describing a DMB restricted reception service according to an embodiment of the present invention.

Referring to FIG. 4, the DMB restricted reception service area according to an embodiment of the present invention includes a main broadcasting network 310, a relay network 320, and an area 330 in which the main broadcasting network coverage and the relay network coverage overlap.

In the main broadcasting network 310, a main broadcasting network transmitting station 311 is provided, and the subscriber station receives the main broadcasting station TIIa and the control word transmitted from the main broadcasting network transmitting station 311 and decodes the broadcasting signal to receive the broadcasting signal. Become.

In the relay network 320, a relay station 321 is provided, and the extended service subscriber stations 322 and 323 receive an encrypted broadcast signal inserted with the relay station TIIb transmitted from the relay station 321. In this case, the ECM / EMM and the matching key are delivered to the extended service subscribers 322 and 323 in the relay network 320 from the user authentication server 231 through a DMB network or a wireless network. 322 and 323 may receive a broadcast, but the general subscriber may not receive the broadcast.

Further, in the region 330 where the main broadcasting network coverage and the relay network coverage overlap, the subscriber station 331 receives the main broadcasting station TIIa transmitted from the main broadcasting network transmitting station 311 or the relay station TIIb transmitted from the relay station 321.

5 is a diagram illustrating an encrypted broadcast signal between a main broadcast network and a relay network according to an embodiment of the present invention.

Referring to FIG. 5, first, an encrypted broadcast signal is transmitted in the T-DMB main broadcasting network 410 as follows.

When video 412a, audio 412b and data 412c are provided from several program providers, respectively, they are multiplexed into a transport stream by the service multiplexer 414, where the multiplexed transport stream is generated by the TIIa generator 415. It is scrambled by the scrambler 413 using the control word generated by the session key corresponding to the TIIa.

Thereafter, the TIIa generated by the TIIa generator 415 is multiplexed by the encryptor 416 and transmitted by the main broadcasting network transmitting station 411. At this time, the TIIa is located in the header part of the data structure of the encrypted broadcast signal, and the scrambled transport stream composed of the video 412a, the audio 412b, and the data 412c is located in the body part of the data structure.

Next, the encrypted broadcast signal is received in the T-DMB relay network 420 as follows.

The broadcast signal transmitted by the main broadcasting network transmitting station 411 is received through the relay station 421. At this time, the TIIb inserter 422 of the repeating station multiplexes / modulates the TIIb transmitted from the main broadcasting network transmitting station 411. In this case, the TIIa of the header portion is changed to TIIb, and the video / audio / data is transmitted as the broadcast signal originally transmitted from the main broadcasting station.

That is, when the main broadcasting network scrambles the transport stream using the control word and inserts the TII value into the synchronization channel, if the signal is transmitted to the relay network as it is, the relay network changes the TIIa of the synchronization channel to TIIb and the data remains as it is. send. Therefore, if the data is identical to each other and only received within a predetermined delay in the SFN, no interference occurs between the synchronization channels, and since different values can be distinguished from the synchronization channel, different TII values may be detected in the overlapping areas of the main broadcasting network and the relay network. Can be.

Therefore, the general subscriber can receive only the TIIa received from the main broadcasting station network. Since the relay network transmits the relay station TIIb differently from the main broadcasting station TIIa, the general subscriber can receive the main broadcasting network but cannot receive it from the relay network. In addition, the extended service subscriber can be received in the main broadcasting network, and the relay network can reproduce the encrypted broadcast signal only by receiving a matching key for knowing the TIIa through the DMB network or the wireless network.

In other words, in case of a general subscriber station, only the TIIa value of the main broadcasting station can be received, but in the case of an extended subscriber station capable of using a relay network, it is similar to a general subscriber in the main broadcasting network, but in a relay network, matching is performed through the TIIb value of the relay network and a separate network. Receive the key. In this case, the separate network is classified into a DMB network or a wireless network. If there is no wireless modem like a vehicle type or a dedicated receiver according to the type of terminal, the matching network receives and decrypts a matching key through a high-speed information channel (FIC) of its own DMB. .

If there is a wireless modem, the matching key is transmitted through the corresponding wireless network. In case of general subscriber, only TIIa value received from main broadcasting station network can be received, but if it does not receive matching key for decryption from relay network separately, it cannot be received from relay network. In the relay network, the matching key received through the network illustrated above can be received. In this case, since the signal is not broken when the main broadcasting network and the relay network are identical to each other, the FIC transmits the same ECM and EMM as the relay network in the main broadcasting network region.

On the other hand, a problem in the above-mentioned transmission part is that when the general subscriber stores the TIIa received in the main broadcasting network and moves to the relay network, the general subscriber may be able to receive even in the relay network. In order to solve this problem, the encryption server in the main broadcasting station periodically changes the main broadcasting station TIIa, and accordingly, the scrambling of the transport stream also applies the changed TIIa.

In addition, if the TIIa of the main broadcasting network includes CW, an error may occur in a mobile environment, and since a received signal cannot be decoded correctly, some bits of the TII symbols may be error corrected codes to enhance error correction for CW. (Error correction code: ECC).

6 is a diagram illustrating a transmission signal for each channel of the main broadcasting network and the relay network according to an embodiment of the present invention.

Referring to FIG. 6, in the main broadcasting network 510, the broadcasting station identification information TIIa and the control word 512 of the main broadcasting station are alternately transmitted to the synchronization channel (SC) 511, and the received information is transmitted to the fast information channel 513. In order to decrypt, ECM and EMM 514, which is encryption information, are sent. In addition, the transmitting station identification information TIIb of the relay station is sent to the synchronization channel 521 of the relay network 520, and the ECM and EMM 524, which are encryption information, are sent to the FIC channel 523 to decode the received data. send.

Specifically, the transmission frame according to the embodiment of the present invention is composed of a synchronization channel (SC), a fast information channel (Fast Information Channel) and a main service channel (MSC).

The synchronization channel consists of a null symbol and a phase reference symbol (PRS), and a TII signal is applied to a null symbol. The synchronization channel includes transmission mode and information necessary for symbol and frequency synchronization. The synchronization channel is also used for frame synchronization, carrier frequency synchronization, channel state estimation, basic demodulation functions, and the like.

The fast information channel includes a service information (SI), a fast information data channel (FIDC), a multiplex configuration information (MCI), and a conditional access (CA). The MCI, a component of the FIC, is transmitted to the receiver as information on the type, location, and type of service of the MSC and used to interpret the MSC. Here, the SI may include a service title, channel information, and the like.

7 is a diagram exemplifying transmission station identification information and control word transmitted through a synchronization channel in a main broadcasting network transmitting station according to an embodiment of the present invention.

Referring to FIG. 7, a method of transmitting transmission station identification information and a control word (CW) of a main broadcasting station through a synchronization channel in the main broadcasting network is illustrated. Normally, the control word (CW) is allocated with 64 bits. If the frame range that can be sent with the sending station identification information TIIa is 8 bits, the synchronization of 8 frames to transmit the 64-bit control word (CW) is performed. The channel will be sent separately. After the control word (CW) is transmitted, the main broadcasting station transmitting station identification information TIIa which can distinguish the main broadcasting station is transmitted again. Here, reference numerals 610a, 610b, and 611a to 611n represent a synchronization channel (SC), reference numerals 620a and 620b represent a main broadcasting station identification information TIIa, and 630a to 630n are control words (CW1) divided into transmission channels and transmitted. , CW2, ..., CWn).

9 is a block diagram of a subscriber station of a DMB conditional access system according to a sending station according to an embodiment of the present invention, where the subscriber station may be a dedicated terminal or a mobile phone terminal.

9, the subscriber station 800 of the DMB limited reception system according to the transmitting station according to the embodiment of the present invention, the transmission and reception antenna 810, RF module 820, TII detection unit 830, decoder 840 The controller 850 may include a matching unit 860, a control word generator 870, and a display 880, and may further include a wireless modem 890 in some cases.

When the encrypted RF broadcast signal is received through the antenna 810, the RF module 820 selects a corresponding channel and converts the received broadcast signal into a digital signal.

The TII detector 830 detects and outputs a TII value, which is a transmitting station identification information, from a broadcast signal output from the RF module 820.

The matching unit 860 may include a matching algorithm in a program form that can identify the sending station identification information using the matching key. That is, the matching unit 860 includes a matching function for extracting a TII value, which is the transmission station identification information of the main broadcasting station, corresponding to the TII value detected by the TII detection unit 830 in a program form, and the matching unit 860 ) Can identify the TIIa which is the identification information of the broadcasting station of the main broadcasting station through this matching algorithm. Also, the matching unit 860 matches and outputs a session key corresponding to TIIa, which is the transmission station identification information of the main broadcasting station, using a key table having the same contents as the key table shown in FIG.

The control word generator 870 generates the control word using the session key output from the matching unit 860.

When the signal output from the RF module 820 is an encrypted broadcast signal, the decoder 840 decodes and outputs a broadcast signal using the control word generated by the control word generator 870. The video data decoded by the decoder 840 is displayed.

The controller 850 controls the overall operation of the subscriber station 800, in particular, identifies the TII value detected by the TII detection unit 830, and determines that the transmitting station of the broadcast signal is the relay station based on the identified TII value. In order to determine TIIa, which is the transmission station identification information of the main broadcasting station corresponding to the TII value, the TII value is transmitted to the matching unit 860, and the control word generated by the control word generation unit 870 can be used by the decoder 840. To pass. Here, the matching key may be given only when the subscriber station 800 is an extended service subscriber. That is, in the case of the general service subscriber in the relay network, since the matching key is not given, the encrypted broadcast signal cannot be decrypted, so that the DMB reception cannot be received.

On the other hand, the matching unit 860 may include a matching algorithm for finding out the sending station identification information using the matching key and a matching algorithm for finding the session key corresponding to the sending station identification information in a program form. That is, the matching unit 860 corresponds to a matching function capable of extracting TIIa value of the broadcasting station identification information of the main broadcasting station corresponding to the TII value detected by the TII detecting unit 830 and a TIIa value of the broadcasting station identification information of the main broadcasting station. The matching function for extracting the session key may be embedded in a program form, and the matching unit 860 may identify the TIIa, which is the sending station identification information, and the corresponding session key through the matching algorithm.

In addition, when the subscriber station 800 is a dedicated terminal without the wireless modem 880 which is a communication module, the subscriber terminal 800 receives a matching key through the DMB network. In addition, when the subscriber station 800 is a mobile phone terminal having a wireless modem 880, the matching key is wirelessly transmitted through the wireless network by the authentication system, wherein the matching key is a unique number of the subscriber station 800 By using the encryption, the matching key can be decrypted only in the corresponding subscriber station 800 to prevent hacking.

Hereinafter, a DMB restriction reception method according to a transmitting station in a general subscriber station according to an embodiment of the present invention will be described with reference to FIG. 10.

First, when a main broadcasting station or a relay station (or a repeater in a shaded area) transmits an encrypted broadcast signal, the general subscriber station 800 is encrypted from the main broadcasting station or relay station through the transmission / reception antenna 810 and the RF module 820. A broadcast signal is received (S901). In addition, the TII transmitted through the synchronization channel SC together with the broadcast signal is detected (S902).

Next, the control unit 850 is transmitted with the encrypted broadcast signal to check whether the TII detected by the TII detection unit 830 is TIIa, which is identification information of the broadcasting station of the main broadcasting station (S903). At this time, the transmitting station identification information TIIa and the control word are included in the encrypted broadcast signal received from the main broadcasting station, and only the transmitting station identification information TIIb is included in the encrypted broadcasting signal received from the relay station.

If the detected TII is the TIIa of the main broadcasting station, the decoder 840 descrambles the encrypted broadcast signal using a control word included in the broadcast signal (S904), and displays it on the display 870 (S905). ).

Here, since the TIIa and the control word CW are changed every predetermined period from the main broadcasting station, the above-described steps S903 to S905 are repeated.

On the other hand, when the TII is not the TIIa of the main broadcasting station, that is, in the step S903, that is, the TII is the TIIb of the relay station, the counter value embedded in the general subscriber station is increased (S906). This is for the case where the general subscriber station enters the relay network through the overlapping network in the main broadcasting network.

Next, it is checked whether the counter value is a predetermined period (S907), and the step S907 is repeated until the predetermined period, that is, the time elapses.

Next, when the counter value corresponds to a predetermined period, the counter is reset, and from this time, the general subscriber station is restricted from receiving the encrypted broadcast signal (S908).

Of course, when the general subscriber station is in the relay network from the beginning, reception of the encrypted broadcast signal may be restricted from the beginning regardless of the counter value. Therefore, when the subscriber station is not an extended service subscriber station subscribed to a service capable of receiving an encrypted broadcast signal, broadcast reception is restricted in the relay network.

Next, a method for receiving DMB restriction according to a sending station of an extended service subscriber station according to an embodiment of the present invention will be described with reference to FIG. 11.

First, when a main broadcasting station or a relay station (or a repeater in a shaded area) transmits an encrypted broadcast signal, the extended service subscriber station 800 receives the encrypted broadcast signal through the transmit / receive antenna 810 and the RF module 820. (S1001). The TII detector 830 detects a TII transmitted together with the broadcast signal from the synchronization channel SC (S1002). In this case, the TII may be detected in the synchronization channel SC.

Next, the TII transmitted together with the encrypted broadcast signal is detected by the TII detector 830, and the controller 850 checks whether the detected TII is TIIa of the main broadcasting station (S1003). At this time, the transmitting station identification information TIIa and the control word are included in the encrypted broadcast signal received from the main broadcasting station, and only the transmitting station identification information TIIb is included in the encrypted broadcasting signal received from the relay station.

If the detected TII is the TIIa of the main broadcasting station, the decoder 840 descrambles the encrypted broadcast signal using the control word included in the broadcast signal (S1004), and displays it on the display 870 (S1005). ).

Here, since the TIIa and the control word CW are changed every predetermined period from the main broadcasting station, the above-described steps S1003 to S1005 are repeated.

On the other hand, if the TII is not the TIIa of the main broadcasting station in step S1003, that is, if the TII is the TIIb of the relay station, the extended service subscriber station 800 is TIIa, which is the identification information of the broadcasting station of the main broadcasting station through the DMB broadcasting network or the wireless network. The matching key for knowing is provided from the authentication system (S1006). As described above, when the extended service subscriber station 800 is provided with the wireless modem 880, a matching key is provided through the wireless network, or when the extended service subscriber station 800 is not provided with the wireless modem, the ECM / You will be provided with a matching key in EMM format.

Accordingly, the matching unit 860 of the controller 850 detects TIIa, which is the sending station identification information corresponding to TIIb, using the matching key (S1007), and detects a session key corresponding to the detected TIIa (S1008).

Thereafter, when the control word generator 870 generates the control word CW using the session key detected in the step S1007 (S1009), the decoder 840 receives and uses the control word CW. After descrambled the encrypted broadcast signal (S1004), it is displayed on the display 870 (S1005).

As described above, referring to FIGS. 10 and 11, when the extended service subscriber station is in a relay network, the above-described authentication system transmits a matching key used to decrypt the encrypted broadcast signal at the request of the extended service subscriber station. Done. As described above, when the general subscriber station is in the relay network area, reception is restricted by the encryption broadcast signal, and in order to release it, the subscriber station should be changed to the extended service subscriber station and after receiving the matching key from the authentication system. The encrypted broadcast signal can be decoded.

While the invention has been shown and described in connection with specific embodiments thereof, it will be appreciated that various modifications and changes can be made without departing from the spirit and scope of the invention as indicated by the claims. Anyone who owns it can easily find out.

According to the present invention, when a separate relay network other than the main broadcasting network is constructed for the shadow area, the main broadcasting network operator can expand the broadcasting network by differentiating the access of the general subscriber terminal and the extended service subscriber terminal, and the repeater operator can repeat the relay network. You can revitalize your business.

Claims (12)

In the system for receiving limited reception of digital broadcasting based on DMB (Digital Multimedia Broadcasting) method according to the transmitting station, A transmitter identification information detection unit for detecting transmitter identification information (TII) in an encrypted broadcast signal received through an antenna; A matching unit which finds transmission station identification information of a main broadcasting network corresponding to the transmission station identification information detected by the transmission station identification information detection unit and outputs a corresponding session key; A control word generation unit generating a control word using a session key output from the matching unit; A decoder that decodes the received encrypted broadcast signal using the control word generated by the control word generator; And Encryption received by controlling the broadcasting station identification information detecting unit, the matching unit, the control word generating unit, and the decoder according to whether the broadcasting network to which the transmitting station belongs according to the transmitting station identification information detected by the transmitting station identification information detecting unit and whether the system subscribes to the extended service For decoding the broadcast signal Digital broadcast limited reception system comprising a. The method of claim 1, And the matching unit finds transmission station identification information of a main broadcasting network corresponding to the transmission station identification information detected by the transmission station identification information detection unit using a matching key received from the outside. The method of claim 2, And a wireless modem for receiving the matching key from the outside through a wireless network and transmitting the matching key to the matching unit. The method of claim 2, And the control unit receives the matching key from the outside through the DMB network and transmits the matching key to the matching unit. The method of claim 1, The control unit, When it is determined that the encrypted broadcast signal is transmitted from a transmitting station belonging to a main broadcasting network by analyzing the transmitting station identification information detected by the transmitting station identification information detecting unit, the decoder uses the control word included in the encrypted broadcasting signal. To decrypt the encrypted broadcast signal. Digital broadcast limited reception system, characterized in that. The method of claim 1, The control unit, If the encrypted broadcast signal is transmitted from a transmitting station belonging to a relay network by analyzing the transmitting station identification information detected by the transmitting station identification information detecting unit, and it is determined that the system is subscribed to an extended service, the decoder generates the control word. Controlling to decrypt the encrypted broadcast signal using a control word generated in Digital broadcast limited reception system, characterized in that. The method according to claim 2, wherein And the matching key is periodically received from the outside. Claims [1] A method for an extended service subscriber system to receive a digital broadcasting based on DMB (Digital Multimedia Broadcasting) according to a sending station. a) receiving, by the extended service subscriber system, an encrypted broadcast signal from a main broadcasting station or a relay station; b) detecting originating station identification information from the synchronization channel; c) checking whether the detected broadcasting station identification information is the broadcasting station identification information of the main broadcasting station; d) if it is determined that the detected broadcasting station identification information is not the broadcasting station identification information of the main broadcasting station, the extended service subscriber system receiving a matching key from the outside through the DMB network or the wireless network; And e) decoding the received encrypted broadcast signal using the matching key and the detected transmitting station identification information; Digital broadcast restriction reception method comprising a. The method of claim 8, Step e), Detecting identification information of a main broadcasting station corresponding to the detected broadcasting station identification information using the matching key; Detecting a session key corresponding to the detected identification information of the main broadcasting station; Generating a control word using the detected session key; And Decrypting the encrypted broadcast signal using the generated control word; Digital broadcast restriction reception method comprising a. The method of claim 8, In step c), if it is determined that the detected transmitting station identification information is the transmitting station identification information of the main broadcasting station, the extended service subscriber system uses the control word included in the encrypted broadcasting signal to receive the encrypted broadcasting signal. Digital broadcast restriction receiving method further comprising the step of decoding. In the method for receiving a digital broadcasting based on the Digital Multimedia Broadcasting (DMB) scheme by the general service subscriber system according to the sending station, a) the general subscriber system receiving an encrypted broadcast signal from a main broadcasting station or a relay station; b) detecting originating station identification information from the synchronization channel; c) checking whether the detected broadcasting station identification information is the broadcasting station identification information of the main broadcasting station; And d) if it is determined that the detected broadcasting station identification information is not the broadcasting station identification information of the main broadcasting station, decoding the encrypted broadcasting signal by using the control terminal included in the encrypted broadcasting signal; Digital broadcast restriction reception method comprising a. The method of claim 11, In step c), if it is determined that the detected transmitting station identification information is not the transmitting station identification information of the main broadcasting station, increasing a counter value provided in the general subscriber system; Checking whether the counter value is equal to a period value set by a main broadcasting station; And If it is determined that the counter value is equal to the period value set by the main broadcasting station, resetting the counter value to stop decoding of the encrypted broadcast signal to limit broadcast signal reception; Digital broadcast restriction reception method comprising a.

Images