KR20060132373A - Data structure and method for charged mobile-type broadcasting, and mobile-type broadcasting receiver - Google Patents

Abstract

A data structure and a method for a charged mobile-type broadcasting service, and a mobile-type broadcasting receiver are provided to retransmit a DMB service after changing a frame structure when retransmitting the DMB(Digital Multimedia Broadcasting) service, received in a charged gap filler, thereby providing a service of high quality to paid service subscribers even in a dead zone without disturbing free service users. A data structure for a charged mobile-type broadcasting service comprises the followings: an SYNC(Synchronization Channel) where a KRS(Key Reference Symbol), a PRS(Phase Reference Symbol) encrypted on the basis of the KRS, and a null symbol are located in order; and an MSC(Main Service Channel) where service data is actually transmitted. Configuration information of a data channel, transmitted from the MSC, is transmitted in an FIC(Fast Information Channel). The FIC is composed between the SYNC and the MSC.

Description

Data structure and method for charged mobile-type broadcasting, and mobile-type broadcasting receiver}

1 (a) is a diagram showing the structure of a typical DMB transmission frame

1 (b) is a view showing the structure of a DMB transmission frame according to an embodiment of the present invention

2 is a schematic diagram of a mobile broadcast receiver for a paid DMB service according to an embodiment of the present invention;

3 is an operation flowchart for a paid DMB service according to an embodiment of the present invention;

Explanation of symbols for main parts of the drawings

201: tuner 202: A / D conversion unit

203: null / PRS detection unit 204: FFT unit

205: PRS compensator 206: key address detector

207: key table 208: channel decoding unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile broadcast receiver, and more particularly, to a data structure, a method, and a mobile broadcast receiver using the same for a paid DMB service in a terrestrial digital multimedia broadcasting (DMB) receiver.

Digitalization of broadcasts has also affected existing analog radio broadcasts, which has led to the advent of digital radio broadcasts. In addition to the existing voice radio services, digital multimedia broadcasting (DMB) services including data transmission and multimedia services are now possible.

The terrestrial DMB service adopted in Korea is based on Eureka-147 Digital Radio Broadcasting (DAB), adopted as the European terrestrial radio standard. Added to improve multimedia broadcasting performance, RS codes (Reed-Solomon Code) and convolutional interleaver that are robust against burst errors that may occur on a transmission channel are added.

Therefore, the DMB service is robust against noise and distortion on a transmission channel, has a high transmission efficiency, and has various advantages of enabling various multimedia services.

In addition, the DMB transmission channel is a wireless mobile reception channel, and the amplitude of the received signal is not only time-varied, but also the Doppler Spreading of the spectrum of the received signal occurs due to the influence of the mobile receiver. . In consideration of the transmission and reception in such a channel environment, the DMB transmission scheme is based on Orthogonal Frequency Division Multiplexing (OFDM). Since the OFDM scheme uses a plurality of multiple carriers, it is very resistant to ghosts generated by the multipath channel, and channel estimation based on a pilot signal is easy.

Although the Eureka-147 was created for digital audio broadcasting (DAB), the Eureka-147 is also used as a technology for terrestrial DMB that uses a narrow frequency bandwidth of 2 MHz to serve a video of a small screen size. In other words, the Eureka-147 system has a packet or stream mode that can be extended to transmit multimedia data. Therefore, the existing terrestrial DAB system can be used to transmit multimedia data with minimal changes.

In the Eureka-147 system, one broadcast service may be configured with a plurality of service components, and multiple broadcasts may be multiplexed and transmitted through about 2Mhz frequency band.

That is, the Eureka-147 system transmits data through repetitive transmission of a unit structure called a frame. The transmission frame is a synchronization channel (SYNC) for signal synchronization and actual service data as shown in FIG. A main service channel (MSC) to be transmitted, and a fast information channel (FIC) through which configuration information of a data channel transmitted through the MSC is transmitted.

The synchronization channel has a certain form defined to recognize that the DMB receiver is the beginning of the frame, and carries information for decoding in digital communication. That is, the synchronization channel is composed of a null symbol for transmitting no signal and a phase reference symbol (PRS) for π / 4-DQPSK modulation and demodulation.

The MSC is composed of one or more Common Interleaved Frames (CIFs), and is used for transmitting broadcast services (ie, video services, audio services, and data services) to be actually broadcast. Since data must be transmitted without error in this channel, error correction data other than the actual data is transmitted together. In other words, video services, audio services, and data services are transmitted to the MSC. In the FIC, the actual data is transmitted to which channel in the MSC and other necessary information.

In the FIC, error correction data other than the CRC is not transmitted because it is intended for fast information transfer. The FIC is composed of a plurality of FIBs, and is used for transmitting various information for receiving a broadcast service.

In this case, the synchronization channel, the FIC, and the MSC part are composed of a plurality of Orthogonal Frequency Division Multiplexing (OFDM) symbols. For example, in transmission mode 1, the PRS of a synchronization channel is composed of one OFDM symbol, and the FIC and the MSC are each composed of three and 72 OFDM symbols. In this case, each OFDM symbol in one frame is differentially encoded based on the PRS.

That is, in the DMB transmitter, each service (audio, video, data service) is individually encoded for error prevention, interleaved in the time domain, and each service interleaved in the time domain is multiplexed and combined into an MSC, which is a data channel. . The multiplexed signal is interleaved in the frequency domain together with the multiplexing configuration information (MCI) and service information (Service Informaton (SI)) transmitted to the control channel FIC. At this time, since information transmitted to the FIC does not allow time delay, time domain interleaving is not performed. The frequency interleaved bit stream is mapped to a differential quaternary phase shift keying (DQPSK) symbol and becomes an OFDM symbol through an inverse fast Fourier transform (IFFT). The OFDM symbol is modulated into an RF signal and transmitted.

In this case, since the terrestrial DMB service is required to provide multimedia services regardless of location, the installation of a gap filler for a shadow area of a city such as a building or a subway is very important for quality of service.

That is, the gap filler is installed in a shaded area where DMB service is difficult to receive by subways, dense buildings, and high-rise buildings, and the mobile broadcast receiver in the shaded area receives DMB service by receiving and retransmitting DMB service transmitted from a broadcasting station. It's a kind of relay device that makes it possible.

However, since terrestrial DMB service is basically a free service, the service provider has a lot of cost burden in securing a service area by installing a gap filler.

The present invention is to solve the above problems, an object of the present invention is to allow the user who wants to receive the DMB service in the service shadowed area, when receiving the retransmitted signal through the gap filler pay the fee and receive the DMB service data It is to provide a structure, a method, and a mobile broadcast receiver using the same.

In order to achieve the above object, a transmission frame of a signal for a pay mobile broadcast service in a data structure for a pay DMB service according to an embodiment of the present invention,

A synchronization channel in which encryption information symbols, a phase reference symbol (PRS ') encrypted based on the encryption information, and null symbols are sequentially located;

A main service channel (MSC) through which actual service data is transmitted; And

The fast information channel (FIC) through which the configuration information of the data channel transmitted through the MSC is transmitted is configured between the synchronization channel and the MSC.

Method for a pay mobile broadcast service according to the present invention,

(a) encrypting a phase reference symbol (PRS) of a synchronization channel in a transmission frame for a pay mobile broadcast service, and transmitting the synchronization channel in the order of encryption information, an encrypted PRS, and a null symbol used for the encryption;

(b) determining whether a pay mobile broadcast service is available if a mobile broadcast service is received;

(c) if it is determined in step (b) that the pay mobile broadcast service is possible, determining whether the received mobile broadcast frame is a frame for the pay mobile broadcast service; And

(d) If it is determined as the frame for the pay mobile broadcast service in step (c), the PRS is recovered by decrypting the encrypted PRS based on the encryption information in the frame, and the FIC and MSC of the frame is determined based on the restored PRS. It is characterized in that it comprises a step of decoding each OFDM symbol.

Step (a) is to encrypt the phase reference symbol (PRS) of the synchronization channel in the frame in the pay gap filler installed for the pay mobile broadcast service, and retransmitted in the order of the encryption information, the encrypted PRS, null symbols used for the encryption It features.

In step (a), a broadcast station providing a mobile broadcast service encrypts a phase reference symbol (PRS) of a synchronization channel in a frame for a pay mobile broadcast service, followed by encryption information, encrypted PRS, and null symbol used for the encryption. It characterized in that the transmission.

The mobile broadcast receiver according to the present invention detects a null symbol from a received mobile broadcast service signal and detects whether or not a received mobile broadcast service signal is a signal for a pay mobile broadcast service based on the detected null symbol. A PRS detector; An encryption information detector for detecting encryption information from the mobile broadcast service signal when the null / PRS detector is determined to be a service signal for a pay mobile broadcast service; And when the null / PRS detector is determined to be a service signal for a pay mobile broadcast service, decrypts an encrypted PRS from the mobile broadcast service signal based on the encryption information detected by an encryption information detector, restores the PRS, and restores the restored PRS. It is characterized in that it comprises a decoding unit for decoding each OFDM symbol of the FIC, MSC in the frame as a reference.

And the null / PRS detector detects whether a received mobile broadcast service signal is a signal for a pay mobile broadcast service based on a channel impulse response to a PRS before and after a null symbol.

The encryption information detector detects a key address by decoding encryption information located in a synchronization channel in the received mobile broadcast service signal, and outputs a key value corresponding to the key address detected by the key address detector to the decoder. And a key table.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention that can specifically realize the above object will be described. At this time, the configuration and operation of the present invention shown in the drawings and described by it will be described as at least one embodiment, by which the technical spirit of the present invention and its core configuration and operation is not limited.

The term used in the present invention was selected as a general term widely used as possible at present, but in some cases, the term is arbitrarily selected by the applicant, in which case the meaning is described in detail in the description of the invention, the name of a simple term The present invention is to be understood as the meaning of the term rather than the present invention.

First, the present invention defines a gap filler installed for paying DMB service for convenience of description, a paid gap filler, and a gap filler installed for existing free service, as a free gap filler. In addition, users of mobile broadcast receivers that can use retransmitted signals from paid gap fillers as well as free gap fillers and broadcasting stations are called paid DMB service users, and users of mobile broadcast receivers who cannot use retransmitted signals from paid gap fillers are users of free DMB service users. It is defined as

In this case, the user of the mobile broadcast receiver may register as a paid DMB service user in advance, or select whether to receive a retransmitted signal from the pay gap filler without additional registration (that is, subscription), and, if selected, according to a preset condition. You may be charged a fee. Here, the preset conditions may be various, for example, the viewing time of the DMB service retransmitted in the pay gap filler. In this case, when the user selects the reception of the retransmitted signal from the pay gap filler, the pay DMB service user becomes a user.

If the user is registered as a paid DMB service user in advance, the user may use the paid gap filler's DMB service for a fee or charge a fee only when using the paid gap filler's DMB service. In the latter case, it is preferable to allow the user to select whether to receive the retransmitted DMB signal in the pay gap filler through the mobile broadcasting receiver as in the method of using the paid DMB service of the non-subscriber. In this case, information such as fee information and whether or not to pay may be provided to the user through a corresponding mobile broadcast receiver in the form of text or sound. On the other hand, when manufacturing a mobile broadcast receiver can be produced by distinguishing between free and free. In this case, it is better to sell the receiver with a differential price.

In the present invention, a mobile broadcast receiver is subscribed to a paid DMB service according to an embodiment, and a fee is set as an embodiment.

In addition, the pay gap filler installed to charge DMB service of the present invention changes the frame structure at the time of retransmission of the signal transmitted from the broadcasting station, thereby allowing the pay DMB service user to make high-quality DMB in a shadow area such as a building or subway. Make sure you get services.

That is, the free gap filler simply retransmits a signal transmitted from a broadcasting station without changing the frame structure, and the paid gap filler changes and retransmits the frame structure so that only the paying user can use it.

In particular, when the pay gap filler of the present invention retransmits the DMB service transmitted from the broadcast station, it is characterized in that the retransmission by changing the synchronization channel interval of the received DMB transmission frame.

Therefore, the user of the free DMB service can use only the DMB service transmitted from a broadcasting station or a free gap filler, so that the DMB service cannot be used in the shadow area or the low quality DMB service is provided.

On the other hand, users of the paid DMB service can use all of the DMB services transmitted from broadcasting stations, free gap fillers, and paid gap fillers, so that they always receive high-quality DMB services regardless of the shadow area. That is, the existing free DMB service user does not interfere with receiving a signal transmitted from a gap filler for a broadcasting station or a free DMB service, and the paid DMB service user can receive a high quality DMB service in a shadow area.

In one embodiment, the paid gap filler of the present invention encrypts the PRS of the synchronization channel as shown in FIG. 1 (b), and encrypts the encryption information (KRS) and the encrypted PRS (PRS ') used for encryption. And retransmit.

In an embodiment of the present invention, a PRS encrypted in a pay gap filler is defined as a PRS 'symbol, and encryption information used to encrypt the PRS is defined as a key reference symbol (KRS). That is, the KRS is an encryption key table reference symbol and encrypts the PRS by reading encryption information corresponding to the KRS value from the key table.

In this case, the KRS and the key table are required to decrypt the encrypted PRS (PRS ') in the pay mobile broadcast receiver. Therefore, the KRS is inserted into a transmission frame together with the encrypted PRS (PRS ') and transmitted to the receiver, and the key table is transmitted to the receiver through a communication network such as CDMA or the Internet. The key table is updated at regular intervals (for example, one month) to prevent hacking. The KRS is also changed and transmitted at regular intervals. In this case, the predetermined period may be a time (for example, 1 minute). Alternatively, it may be changed based on the CIF value constituting the MSC.

The KRS and the PRS 'are located before the null symbol in the synchronization channel in the transmission frame as shown in FIG.

That is, the synchronization channel in the transmission frame retransmitted in the pay gap filler of the present invention has a structure of KRS symbol + PRS 'symbol + null symbol. In other words, the KRS is located between PRS 'and the last MSC of the previous transmission frame. For example, assuming that one transmission frame duration is 96ms, that is, mode 1, the duration of KRS is set to 51us and the duration of PRS 'is set to 1.246ms. In this case, the duration of the null symbol is set to 1.246 ms.

The PRS transmitted after the null symbol by the broadcasting station and the PRS (PRS ') encrypted by the pay gap filler are different information. Therefore, the PRS cannot be detected without decoding the PRS 'symbol in the mobile broadcast receiver.

Therefore, in the present invention, if the receiver is subscribed to the paid DMB service, the synchronization channel can both decode the DMB frame having the null symbol + PRS structure and the DMB frame having the KRS symbol + PRS 'symbol + null symbol structure. According to an embodiment of the present invention, the non-subscribed terminal controls the synchronization channel to be decoded only for a DMB frame having a null symbol + PRS structure.

In this way, existing DMB service users are not interrupted in receiving signals transmitted from broadcast stations or gap fillers for free DMB services, and paid DMB service users can receive high-quality DMB services in shaded areas.

2 is a block diagram illustrating a structure of a mobile broadcast receiver according to an embodiment of the present invention. The tuner 201, the A / D converter 202, the null / PRS detector 203, and the FFT (Fast Fourier Transform) are shown in FIG. Unit 204, PRS compensator 205, key address detector 206, key table 207, and channel decoder 208.

That is, the tuner 201 receives the DMB service signal of a specific channel from the antenna and outputs it to the A / D converter 202. The A / D converter 202 digitizes the received DMB service signal and outputs it to the null / PRS detector 203.

The null / PRS detection unit 203 detects a null symbol from the digitized DMB service signal and determines whether it is a paid DMB service signal based on a channel impulse response (CIR) for the PRS before and after the null symbol. Detect. For example, if the correlation between the PRS signals before and after the null symbol is detected and the maximum value is displayed in front of the null symbol, it is determined as the paid DMB service signal, and if the maximum value is displayed after the null symbol, it is determined as the free DMB service signal. The determination result is output to the PRS compensator 205 and the key address detector 206.

The FFT unit 204 converts the digitized DMB service signal into a frequency domain and outputs it to the PRS compensator 205.

On the other hand, if the null / PRS detection unit 206 determines that the paid DMB service signal is detected by the null / PRS detection unit 203, the key address detection unit 206 decodes the encryption information KRS located in front of the encrypted PRS (PRS ') and detects the key address. 207). The key table 207 outputs a key value corresponding to the detected key address to the PRS compensator 205.

The PRS compensator 205 restores the PRS by decrypting the encrypted PRS (PRS ') using the key value output from the key table 207 when the null / PRS detector 203 determines the pay DMB service signal. do. The reconstructed PRS is output to the channel decoding unit 208.

That is, the PRS compensator 205 bypasses the output of the FFT unit 204 to the channel decoder 208 as it is determined by the null / PRS detector 203 as a free DMB service signal, and pays for the DMB service signal. If it is determined that the PRS (PRS ') is encrypted using a key value and output to the channel decoding unit 208.

The channel decoder 208 differentially decodes each OFDM symbol of the FIC and the MSC based on the PRS output through the PRS compensator 207.

At this time, the key table 207 is updated at regular intervals through the communication network. If the KRS is changed based on the CIF, the channel decoder 208 outputs the CIF count value to the key address detector 206 and the key table 207.

Then, the key address detector 206 detects the key address by decoding the KRS only when the CIF count value used as the KRS change criterion is input. In this case, the key table 207 may also output the key value only when the corresponding CIF count value is input.

3 is an operation flowchart for a paid DMB service according to the present invention. When a DMB service signal is received (step 301), it is determined whether the payable DMB service is a mobile broadcast receiver capable of performing the step (302).

According to an embodiment of the present invention, if the mobile broadcast receiver is subscribed to a paid DMB service and the fee is a flat rate, the mobile broadcast receiver determines that the paid DMB service is possible. In addition, even if the mobile broadcast receiver is subscribed to the paid DMB service, if a fee is charged according to whether or not the user is watching the subscription or viewing time, first, the user is notified of the paid DMB service by text or sound, and whether the paid DMB service is provided. After selecting, it is good to control the paid DMB service only when it is selected. This can be applied even to non-subscribers.

If the mobile broadcast receiver is not subscribed to the paid DMB service, or if the paid DMB service is not selected in a question asking whether to receive the paid DMB service, it is preferable to control the paid DMB service not to be possible.

If it is determined in step 302 that the paid DMB service is not available, the position of the null symbol is detected, and the next OFDM symbol is differentially decoded based on the OFDM symbol following the detected null symbol (step 306).

If it is determined in step 302 that the paid DMB service is not possible and the transmission frame has the structure as shown in FIG. 1 (b), step 306 considers the first OFDM symbol of the FIC as the PRS of the synchronization channel and based on this, Differential decoding of OFDM symbols results in incorrect decoding. That is, in the case of (b) of FIG. 1, since the synchronization channel is KRS + PRS '+ null symbol structure, a null symbol is followed by a FIC and an MSC. In step 306, the first OFDM symbol of the FIC is regarded as a PRS, The next OFDM symbols are differentially decoded based on the first OFDM symbol.

As described above, in the mobile broadcast receiver in which the paid DMB service is not possible, the DMB frame as shown in FIG.

On the other hand, if it is determined in step 302 that the paid DMB service is possible, it is determined whether the demodulated DMB service signal is a signal transmitted from a broadcasting station or a free gap filler or a signal transmitted from a paid gap filler (step 303).

As described above, whether the paid DMB service signal or the free DMB service signal is determined based on the CIR of the PRS before and after the null symbol. Alternatively, each gap filler has a unique identification number (ID), so if the gap filler ID is transmitted when the signal is retransmitted, the mobile broadcast receiver capable of paying DMB service receives the received DMB service signal from the pay gap filler or is a broadcasting station or It is possible to determine whether the signal is transmitted from the free gap filler.

If the DMB frame received in step 303 is determined to be a signal transmitted from a broadcasting station or a free gap filler, the demodulated DMB frame is decoded in a conventional manner (step 306). In this case, the DMB frame structure is shown in (a) of FIG. 1, and the OFDM symbol next to the null symbol is a PRS, so that the OFDM symbols of the FIC and the MSC in the frame are differentially decoded based on the PRS. Therefore, decoding is normally performed.

When the demodulated DMB service signal is determined to be a signal transmitted from the pay gap filler, the mobile broadcast receiver knows the changed frame structure and decodes the PRS 'based on the corresponding encryption information (KRS) to restore the PRS. Step 304). The frame structure is rearranged to a null symbol + PRS structure as shown in FIG. 1A (step 305). Then, the OFDM symbols of the FIC and the MSC are sequentially differentially decoded based on the PRS following the null symbol (step 306).

Therefore, in a region where a signal for a free service transmitted from a broadcasting station or a free gap filler and a signal for a paid service transmitted from a paid gap filler coexist, the conventional mobile broadcast receiver for free reception does not interfere with receiving a free DMB service. do.

That is, in the frame structures of FIGS. 1A and 1B, since different information is transmitted in a null section in which signals are not transmitted, each other does not act as an interference signal. Therefore, when using the paid gap filler retransmitted in the frame structure as shown in Fig. 1 (b) so that the paid DMB service users receive the DMB service even in the shadow area without interrupting the existing free DMB service users receive the free DMB service Do it.

Meanwhile, in the present invention, the pay gap filler is retransmitted by modifying the synchronization channel of the transmission frame as shown in FIG. 1 (b) for the pay mobile broadcast service, but in another embodiment, the broadcast station in FIG. 1 (b) As described above, the synchronization channel of the transmission frame may be changed and transmitted. In this case, the broadcasting station sets up a separate relay network transmission system, and in the relay network transmission system, as shown in (b) of FIG. 1, the synchronization channel of the transmission frame is modified and transmitted to the gap filler. At this time, the optical cable can be transmitted to the gap pulser.

In the present invention, the PRS is encrypted using a key value, but the encryption may be used by changing the scramble or encoding.

That is, the terminologies used in the present invention are terms that are defined in consideration of functions in the present invention and may vary according to the intention or custom of a person skilled in the art, and the definitions of the terminology are used throughout the present invention. It should be based on what has been done.

The present invention is not limited to the above-described embodiments, and as can be seen in the appended claims, modifications can be made by those skilled in the art to which the invention pertains, and such modifications are within the scope of the present invention.

According to the data structure, method, and mobile broadcast receiver for the paid DMB service according to the present invention described above, when the DMB service received by the pay gap filler is retransmitted, the frame structure is changed and retransmitted, thereby causing no damage to the free service user. Without paying, paid service subscribers can be provided with high quality services even in shadow areas.

In addition, the cost of installing the gap filler can be secured to some extent through a paid service, thereby enabling the installation of the gap filler in the shadow area, resulting in the activation of the terrestrial DMB service.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

Claims (17)

The transmission frame of the signal for the pay mobile broadcasting service A synchronization channel in which encryption information symbols, a phase reference symbol (PRS ') encrypted based on the encryption information, and null symbols are sequentially located; A main service channel (MSC) through which actual service data is transmitted; And And a high speed information channel (FIC) in which configuration information of a data channel transmitted through the MSC is transmitted is configured between a synchronization channel and an MSC. A method for a pay mobile broadcast service of a mobile broadcast service system provided with a gap filler for retransmitting a received mobile broadcast signal, (a) encrypting a phase reference symbol (PRS) of a synchronization channel in a transmission frame for a pay mobile broadcast service, and transmitting the synchronization channel in the order of encryption information, an encrypted PRS, and a null symbol used for the encryption; (b) determining whether a pay mobile broadcast service is available if a mobile broadcast service is received; (c) if it is determined in step (b) that the pay mobile broadcast service is possible, determining whether the received mobile broadcast frame is a frame for the pay mobile broadcast service; And (d) If it is determined as the frame for the pay mobile broadcast service in step (c), the PRS is recovered by decrypting the encrypted PRS based on the encryption information in the frame, and the FIC and MSC of the frame is determined based on the restored PRS. And decoding each OFDM symbol. The method of claim 2, wherein step (a) Encrypting the phase reference symbol (PRS) of the synchronization channel in the frame in the pay gap filler installed for the pay mobile broadcast service, and re-transmitted in the order of the encryption information (KRS), the encrypted PRS (PRS '), the null symbol used for the encryption Method for a pay mobile broadcast service, characterized in that. The method of claim 2, wherein step (a) A broadcasting station providing a mobile broadcasting service encrypts a phase reference symbol (PRS) of a synchronization channel in a frame for a pay mobile broadcasting service, and uses encryption information (KRS), encrypted PRS (PRS '), and null symbol used for the encryption. Method for a pay mobile broadcast service characterized in that the transmission in order. The method of claim 2, A frame for a pay mobile broadcast service and a frame for a free mobile broadcast service are distinguished from each other by a synchronization channel. The method of claim 2, wherein step (b) The pay mobile broadcast service characterized in that it is determined whether or not the pay mobile broadcast service is possible by combining at least one of whether the mobile broadcast receiver is subscribed to the pay mobile broadcast service, or whether the pay mobile broadcast service is selected. Way. The method of claim 2, wherein step (d) And if it is determined that the frame is not for a pay mobile broadcast service, decoding the received mobile broadcast service without a PRS decoding process. The method of claim 2, wherein step (c) And if it is determined in step (b) that the pay mobile service is unavailable, decoding the received mobile broadcast service without a PRS decoding process. In the mobile broadcast receiver for receiving a mobile broadcast service transmitted through a broadcast station or a gap filler, A null / PRS detection unit detecting a null symbol from the received mobile broadcast service signal and detecting whether the received mobile broadcast service signal is a signal for a pay mobile broadcast service based on the detected null symbol; An encryption information detector for detecting encryption information from the mobile broadcast service signal when the null / PRS detector is determined to be a service signal for a pay mobile broadcast service; And If the null / PRS detector is determined to be a service signal for a pay mobile broadcast service, the PRS is decoded by decoding the encrypted PRS from the mobile broadcast service signal based on the encryption information detected by the encryption information detector, and the restored PRS is referenced. And a decoding unit for decoding each OFDM symbol of the FIC and the MSC in the frame. The method of claim 9, In the synchronization channel of the service signal for the pay mobile broadcast service, an encryption information symbol (KRS), a phase reference symbol (PRS ') encrypted based on the encryption information, and a null symbol are sequentially located and installed for the pay mobile broadcast service. Mobile broadcast receiver, characterized in that the signal retransmitted by the pay gap filler. The method of claim 9, The synchronization channel of the service signal for the pay mobile broadcast service is a broadcasting station providing a mobile broadcasting service in which an encryption information symbol (KRS), a phase reference symbol (PRS ') encrypted based on the encryption information, and a null symbol are sequentially located. The mobile broadcast receiver, characterized in that the signal transmitted for the mobile payment service. The method of claim 9, And a frame for a pay mobile broadcast service and a frame for a free mobile broadcast service are distinguished from each other by a synchronization channel. The method of claim 9, wherein the null / PRS detection unit And a mobile broadcast service signal detected based on a channel impulse response to a PRS before and after a null symbol for a pay mobile broadcast service. 10. The apparatus of claim 9, wherein the encryption information detection unit A key address detector for detecting a key address by decoding encryption information (KRS) located in a synchronization channel in the received mobile broadcast service signal; And a key table for outputting a key value corresponding to the key address detected by the key address detector to the decoder. 15. The apparatus of claim 14, wherein the key address detection unit And detecting a key address according to a Common Interleaved Frame (CIF) count value constituting a primary service channel (MSC) in the received mobile broadcast service signal. The method of claim 14, And the key table is updated periodically through a communication network. The method of claim 9, wherein the decoding unit When the null / PRS detection unit is determined to be a service signal for a free mobile broadcast service, detecting a PRS based on a null symbol without a PRS decoding process and decoding each OFDM symbol of FIC and MSC in a corresponding frame based on the detected PRS. Mobile broadcast receiver characterized in.

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