KR100641653B1 - Digital television transmitter and receiver for transmitting and receiving dual stream using 4 level vestigial side band robust data - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

VSB DTV transceiver related to ATSC A / 53 and a method thereof.

2. Technical problem to be solved by the invention

Provided is a 4-VSB DTV transceiver and method for improving the reception performance of a receiver by transmitting and receiving a dual stream consisting of general data and robust data without increasing the average power regardless of its mixing ratio.

3. Summary of the Solution of the Invention

If the data stream contains robust data, one of two groups in which the robust data is represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} Encoding means for performing encoding on the robust data to be mapped to a group of.

4. Important uses of the invention

Used for VSB DTV transceiver.

DTV, VSB, Robust Data, General Data

Description

DIGITAL TELEVISION TRANSMITTER AND RECEIVER FOR TRANSMITTING AND RECEIVING DUAL STREAM USING 4 LEVEL VESTIGIAL SIDE BAND ROBUST DATA}             

1 is a block diagram showing a conventional DTV transmitter.

2 is a block diagram showing a conventional DTV receiver.

3 is a configuration diagram of transmission data frames exchanged between the transmitter of FIG. 1 and the receiver of FIG.

4 is a block diagram showing a DTV transmitter according to an embodiment of the present invention.

FIG. 5 is a block diagram illustrating a robust interleaver / packet formatter of FIG. 4.

FIG. 6 is a conceptual diagram illustrating a robust data interleaver of FIG. 5.

7 is a diagram illustrating the structure of the enhanced encoder of FIG. 4 in detail.

FIG. 8 is a conceptual diagram of an embodiment of the enhanced encoder and trellis encoder of FIG. 4 for explaining a process in which general data is output as 8-level symbols and robust data is output as 4-level symbols.

9 is coded into two bits (X ₁ , X ₂ ) normal / strong data symbols such that the trellis encoder of FIG. 4 outputs a four-level signal of {-5, -3, 1, 7} for robust data. One embodiment block diagram illustrating an enhanced encoder.

10 is coded into two bits (X ₁ , X ₂ ) normal / strong data symbols such that the trellis encoder of FIG. 4 outputs a four-level signal of {-7, -1, 3, 5} for robust data. One embodiment block diagram illustrating an enhanced encoder.

FIG. 11 shows two bits such that the trellis encoder of FIG. 4 selectively outputs four-level signals of {-5, -3, 1, 7} or {-7, -1, 3, 5} for robust data. X ₁ , X ₂ ) is an embodiment block diagram illustrating a reinforcement encoder coding into general / strong data symbols.

12 is a conceptual diagram of another embodiment of the enhanced encoder and trellis encoder of FIG. 4 for explaining a process in which general data is output as 8-level symbols and robust data is output as 4-level symbols.

13 is coded into two bits (X ₁ , X ₂ ) normal / strong data symbols such that the trellis encoder of FIG. 4 outputs a four-level signal of {-5, -3, 1, 7} for robust data. Another embodiment block diagram illustrating an enhanced encoder.

14 is coded into two bits (X ₁ , X ₂ ) normal / strong data symbols such that the trellis encoder of FIG. 4 outputs a four-level signal of {-7, -1, 3, 5} for robust data. Another embodiment block diagram illustrating an enhanced encoder.

FIG. 15 shows two bits such that the trellis encoder of FIG. 4 selectively outputs a four-level signal of {-5, -3, 1, 7} or {-7, -1, 3, 5} for robust data. X ₁ , X ₂ ) is another embodiment block diagram illustrating a reinforcement encoder coding into general / strong data symbols.

16 is a diagram for explaining an embodiment of a Z ₀ predicted value D ₃ and a level selection signal.

17 is a detailed block diagram of the robust data processor of FIG.

18 is a view showing field sync segments of a data frame transmitted by the transmitting apparatus 400 of FIG. 4 according to the present invention.

19 is a block diagram showing a DTV receiver according to an embodiment of the present invention.

20 is a detailed block diagram illustrating the control unit of FIG. 19.

21 is a block diagram illustrating the packet formatter / robust deinterleaver of FIG.

FIG. 22 is a conceptual diagram illustrating the robust data deinterleaver of FIG.

Fig. 23 is a state diagram based on the conventional eight levels.

24 is a state diagram based on four levels of {-7, -1, 3, 5} according to an embodiment of the present invention.

FIG. 25 is a graph comparing SNR satisfying TOV of an 8-VSB receiver conforming to ATSC A / 53 standard in an AWGN channel environment.

The present invention relates to a residual side band (VSB) DTV transceiver and a method related to the Digital Television (DTV) standard (A / 53) of the Advanced Television System Committee (ATSC). More specifically, the present invention relates to a DTV transceiver for dual stream transmission and reception using a particular four-level VSB (4-VSB) robust data and a method thereof.

The ATSC standard for High Definition Television (HDTV) transmission over terrestrial broadcast channels uses 12 independent data streams with trellis encoding and time multiplexing for 8 levels of VSB (8-VSB, {-7,-10.76 MHz). 5, -3, -1, 1, 3, 5, 7}) A signal modulated into a symbol stream is used. This signal is converted to a 6 MHz frequency band corresponding to a standard VHF or UHF terrestrial television channel, and the signal on that channel is broadcast at a data rate of 19.39 Mbps per second. Detailed technical information on the ATSC DTV standard and A / 53 is available at http://www.atsc.org/.

1 is a block diagram showing a conventional DTV transmitter.

The data input to the transmitter 100 is a serial data stream composed of 188 bytes of MPEG compatible data packets (including 187 bytes representing sync bytes and payload data). Input data is randomized in the data randomizer 101, and each packet is forward error correction (FEC-RS coding, 1/6 data field interleaving and 2) in the Reed Solomon (RS) encoder 103. / 3 trellis coding) to encode 20 bytes of parity information. That is, according to the ATSC standard, the data randomizer 101 XORs all of the payload data bytes input to a 16-bit maximum length pseudo random binary sequence (PRBS) initialized at the data field start point. do. In the RS encoder 103 receiving the output randomized data, 20 RS parity bytes for FEC are added to 187 bytes of data, thereby generating a total of 207 bytes of data transmitted per data segment. The randomization and FEC processes are not performed on the sync byte corresponding to the segment sync signal among the input packet data.

Next, data packets included in consecutive segments of each data field are interleaved in the data interleaver 105, and the interleaved data packets are interleaved and encoded again in the trellis encoder 107. The trellis encoder 107 generates a stream of data symbols represented by three bits using a two bit input. One bit of the input two bits is precoded, and the remaining one bit is four-state trellis encoded to be two bits. The three bits thus output are mapped to eight-level symbols. The conventional trellis encoder 107 includes 12 parallel trellis encoders and precoders to generate 12 interleaved / coded data sequences.

The eight-level symbol is combined with a segment sync and field sync sync bit sequence 117 from a synchronization unit (not shown) in the multiplexer 109 to generate a data frame for transmission. The pilot signal is then inserted in pilot inserter 111. The symbol stream is VSB suppressed-carrier modulation in the VSB modulator 113. The baseband 8-VSB symbol stream is finally converted into a radio frequency signal by the RF converter 115 and transmitted.

2 is a block diagram showing a conventional DTV receiver.

The RF signal transmitted from the transmitter 100 is channel-selected by the tuner 201 of the receiver 200. Next, the synchronization frequency is detected after the intermediate band (IF) filtering in the IF filter and the detector 203. The synchronization and timing recovery block 215 detects the synchronization signal and restores the clock signal.

The signal is then removed from the NTSC cancellation filter 205 via a comb filter and the NTSC interference signal is removed and equalized and phase tracked by the equalizer and phase tracker 250.

The encoded data symbols from which multipath interference has been removed are trellis decoded in the trellis decoder 209. The decoded data symbols are deinterleaved in the data deinterleaver 211. The data symbol is then RS decoded in the RS decoder 213 and derandomized in the data derandomizer 217. Accordingly, the MPEG compatible data packet transmitted from the transmitter 100 is restored.

FIG. 3 is an arbitrary configuration diagram of a transmission data frame exchanged between the transmitter of FIG. 1 and the receiver of FIG. 2, and as shown in FIG. 3, a transmission data frame includes two data fields, and each data field includes 313 data. It consists of segments.

The first data segment of each data field is a data field sync signal, which is a sync signal, and includes a training data sequence used in the receiver 200. The remaining 312 data segments each contain 20 byte data for FEC in a 188 byte transport packet. The data in each data segment consists of the data contained in several transport packets because of data interleaving. That is, the data of each data segment may correspond to several transport packet data.

Each data segment consists of 832 symbols. The first four symbols are binary and provide data segment sync. The data segment sync signal corresponds to a sync byte, which is the first byte of 188 bytes of an MPEG compatible data packet. Each of the remaining 828 symbols corresponds to 187 bytes of MPEG compatible data packets and 20 bytes for FEC. These 828 symbols are transmitted in eight levels of signal, with each symbol represented by three bits. Therefore, 2484 bits (= 828 symbols x 3) of data are transmitted for each data segment.

However, the transmission signal of the conventional 8-VSB transceiver is distorted in indoor and mobile channel environments due to a variable channel and a multipath phenomenon, resulting in a poor reception performance of the reception device.

That is, the transmitted data is affected by various channel distortion factors. Channel distortion factors include multipath phenomena, frequency offset, phase jitter, and the like. Although the training data sequence is transmitted every 24.2 ms to compensate for the signal distortion caused by the channel distortion factor, the multipath characteristic change and the Doppler interference are not detected even during the 24.2 ms time interval when the training data sequence is transmitted. The receiver cannot perform accurate equalization because the equalizer of the receiver does not have a fast convergence speed enough to compensate for the distortion of the received signal. For this reason, the 8-VSB type DTV broadcasting reception performance is lower than that of the analog type, and it is impossible to receive in a mobile receiver, and the signal to noise ratio (SNR) that satisfies the threshold of visibility (TOV) even if reception is possible There is a problem that increases.

As another conventional technique for solving the problem, a technique of transmitting robust data to any one of four levels of symbols of {-7, -5, 5, 7} or {-7, -3, 3, 7} Although it is disclosed (International Publication No. WO 02/080559, International Publication No. WO 02/100026, United States Patent Publication No. US2002 / 0194570), according to the prior art, the symbol representing robust data is restricted due to the limitation of the symbol to which the robust data is mapped. There is a problem that the average power is increased compared to the conventional 8-VSB method (according to the conventional 8-VSB method, the symbol average power of the robust data is 21 energy / symbol). In other words, if the robust data is any one of the four level symbols {-7, -5, 5, 7}, the symbol average power is 37 energy / symbol, and the robust data is {-7, -3, 3, 7}. In the case of any one of the four level symbols, the symbol average power is 29 energy / symbol, and the average power of the symbol representing the robust data increases compared with the conventional 8-VSB method. The average power rise of symbols representing robust data causes an overall average power increase, and when transmitting signals with limited transmit power (typically), the transmit power of normal data is reduced relative to conventional 8-VSB schemes. There is a problem that in the same channel environment has a poor reception performance than the conventional 8-VSB scheme.

The problem is that as the ratio of robust data mixed with general data increases, the SNR that satisfies the TOV increases. Accordingly, the reception performance is deteriorated even in a good channel environment. There may be situations where no backward compatibility can be provided.

Accordingly, the present invention has been made to solve the above problems, and the general data according to the 8-level VSB (8-VSB) scheme and the additional FEC is performed and robust data following the specific 4-level VSB (4-VSB) scheme. By sending and receiving dual streams without increasing the average power regardless of the mixing ratio, it improves the decoding capability of the equalizer and trellis decoder of the receiver and improves the reception performance of the robust data as well as general data. It is an object of the present invention to provide a DTV transceiver for dual stream transmission and reception using a specific four-level VSB (4-VSB) robust data for lowering the SNR satisfying the SNR.

Those skilled in the art to which the present invention pertains can easily recognize other objects and advantages of the present invention from the drawings, the detailed description of the invention, and the claims.

In order to achieve the above object, the present invention provides a digital signal transmission system comprising: input means for receiving a digital video data stream; If the data stream contains robust data, any of two groups in which the robust data is represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} Encoding means for performing encoding on the robust data to be mapped to one group; And a VSB transmitter for performing VSB modulation on the output signal of the encoder and transmitting the VSB to a VSB receiver.

In order to achieve the above object, the present invention provides a digital signal transmission system comprising: input means for receiving a digital video data stream; When the data stream includes the robust data, any one of two groups in which the robust data is represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} First encoding means for performing encoding on the robust data to be mapped to one group; Second encoding means for performing encoding on the robust data such that the robust data is mapped to a group represented by four levels other than the two groups; Selection means for selectively inputting the robust data into any one of the first encoding means and the second encoding means; And a VSB transmitting means for performing VSB modulation on one of the first encoding means and the second encoding means to transmit to the VSB receiving system.

In order to achieve the above object, the present invention provides a digital signal communication system, comprising: a transmitter; And a receiving device, wherein the transmitting device comprises: input means for receiving a digital video data stream; If the data stream contains robust data, any of two groups in which the robust data is represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} Encoding means for performing encoding on the robust data to be mapped to one group; And VSB transmitting means for performing VSB modulation on the output signal of the encoding means and transmitting the VSB modulation to the receiving device, wherein the receiving device receives and converts a signal transmitted from the transmitting device into a baseband signal. ; Equalizing means for determining a signal level of robust data based on any one of the two groups used by the transmitter; Trellis decoding means for trellis decoding robust data output from the equalizing means based on any one of the two groups used by the transmitter; And a decoding means for decoding the output signal of the trellis decoding means and outputting a digital video data stream.

In order to achieve the above object, the present invention provides a digital signal communication system, comprising: a transmitter; And a receiving device, wherein the transmitting device comprises: input means for receiving a digital video data stream; When the data stream includes the robust data, any one of two groups in which the robust data is represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} First encoding means for performing encoding on the robust data to be mapped to one group; Second encoding means for performing encoding on the robust data such that the robust data is mapped to a group represented by four levels other than the two groups; Selection means for selectively inputting the robust data into any one of the first encoding means and the second encoding means; And VSB transmitting means for performing VSB modulation on one of the output signals of the first encoding means and the second encoding means and transmitting the same to the receiving device, wherein the receiving device receives a signal transmitted from the transmitting device. Wireless receiving means for converting the signal into a baseband signal; The transmission among two groups represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} and a group represented by four levels other than the two groups Equalizing means for determining a signal level of robust data based on any one of the groups used by the apparatus; The transmission among two groups represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} and a group represented by four levels other than the two groups Trellis decoding means for trellis decoding the robust data output from the equalizing means based on any one group used by the apparatus; And decoding means for decoding the output signal of the trellis coding means and outputting a digital video data stream.

In order to achieve the above object, the present invention provides a digital signal receiving system, comprising: wireless receiving means for receiving a signal including digital image data transmitted by a VSB transmission system and converting the signal into a baseband signal; Robust data mapped to any one of two groups represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} is added to the digital image data. Equalizing means for determining a signal level of said robust data based on any one of said two groups used by said VSB transmission system; Trellis decoding means for trellis decoding robust data output from the equalizing means based on one of the two groups used by the VSB transmission system; And decoding means for decoding the output signal of the trellis decoding means and outputting a digital video data stream.

In order to achieve the above object, the present invention provides a digital signal receiving system, comprising: wireless receiving means for receiving a signal including digital image data transmitted by a VSB transmission system and converting the signal into a baseband signal; Mapped to two groups represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} and a group represented by four levels other than the two groups Equalizing means for determining a signal level of the robust data based on any one of the groups used by the VSB transmission system when the robust data is included in the digital video data; Trellis decoding means for trellis decoding robust data output from the equalizing means based on any one of the groups used by the VSB transmission system; And decoding means for decoding the output signal of the trellis decoding means and outputting a digital video data stream.

In addition, to achieve the above object, the present invention provides a digital signal transmission method comprising: a first step of receiving a digital video data stream; If the data stream contains robust data, any of two groups in which the robust data is represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} Performing encoding on the robust data to be mapped to one group; And a third step of performing VSB modulation on the resultant signal of the second step to transmit to the VSB receiving system.

In addition, to achieve the above object, the present invention provides a digital signal transmission method comprising: a first step of receiving a digital video data stream; When the data stream includes the robust data, any one of two groups in which the robust data is represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} Performing encoding on the robust data to be mapped to one group; Performing encoding on the robust data such that the robust data is mapped to a group represented by four levels other than the two groups; A fourth step of selecting one of the second and third steps for encoding the robust data; And a fifth step of performing VSB modulation on the resultant signal of any one of the second and third steps and transmitting the result signal to the VSB receiving system.

In order to achieve the above object, the present invention provides a digital signal communication method comprising: a transmitting step; And a receiving step, wherein the transmitting step comprises: a first step of receiving a digital video data stream; If the data stream contains robust data, any of two groups in which the robust data is represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} Performing encoding on the robust data to be mapped to one group; And a third step of performing VSB modulation on the resultant signal of the second step, and transmitting the received signal, wherein the receiving step comprises: receiving and converting the signal transmitted by the third step into a baseband signal; A fifth step of determining a signal level of robust data based on any one of the two groups used in the transmitting step; A sixth step of trellis decoding the robust data which is a result signal of the fifth step based on any one of the two groups used in the transmitting step; And a seventh step of outputting the digital video data stream by decoding the resultant signal of the sixth step.

In order to achieve the above object, the present invention provides a digital signal communication method comprising: a transmitting step; And a receiving step, wherein the transmitting step comprises: a first step of receiving a digital video data stream; When the data stream includes the robust data, any one of two groups in which the robust data is represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} Performing encoding on the robust data to be mapped to one group; Performing encoding on the robust data such that the robust data is mapped to a group represented by four levels other than the two groups; A fourth step of selecting one of the second and third steps for encoding the robust data; And a fifth step of performing VSB modulation on the result signal of any one of the second and third steps, and transmitting the received signal by receiving the signal transmitted by the fifth step. A sixth step of converting the information into a; The transmission among two groups represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} and a group represented by four levels other than the two groups A seventh step of determining the signal level of the robust data based on any one group used in the step; The transmission among two groups represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} and a group represented by four levels other than the two groups An eighth step of trellis decoding the robust data which is the result signal of the seventh step based on any one group used in the step; And a ninth step of decoding the resultant signal of the eighth step and outputting a digital video data stream.

In order to achieve the above object, the present invention provides a digital signal receiving method comprising: a first step of receiving and converting a signal including digital image data transmitted by a VSB transmission system into a baseband signal; Robust data mapped to any one of two groups represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} is added to the digital image data. A second step of determining a signal level of the robust data based on any one of the two groups used by the VSB transmission system when included; A third step of trellis decoding the robust data which is a result signal of the second step based on any one of the two groups used by the VSB transmission system; And a fourth step of outputting a digital video data stream by decoding the result signal of the third step.

In order to achieve the above object, the present invention provides a digital signal receiving method comprising: a first step of receiving and converting a signal including digital image data transmitted by a VSB transmission system into a baseband signal; Mapped to two groups represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} and a group represented by four levels other than the two groups Determining a signal level of the robust data based on any one of the groups used by the VSB transmission system when the robust data is included in the digital image data; A third step of trellis decoding the robust data which is a result signal of the second step based on any one of the groups used by the VSB transmission system; And a fourth step of outputting a digital video data stream by decoding the result signal of the third step.

According to the present invention, general data is transmitted and received by 8-VSB and robust data is transmitted and received by a specific 4-VSB of {-5, -3, 1, 7} or {-7, -1, 3, 5}. That is, certain 4-VSB robust data packets of {-5, -3, 1, 7} or {-7, -1, 3, 5} are sent to some of the 312 data segments in the data field instead of regular data packets. In this case, the receiver receives error signal calculations for updating the tap coefficient of the equalizer for transmitted 4-VSB robust data and accuracy of the trellis decoder, which reduces the SNR of the 4-VSB robust data as well as 8-VSB general data. Receive performance is also improved.

The following merely illustrates the principles of the invention. Therefore, those skilled in the art, although not explicitly described or illustrated herein, can embody the principles of the present invention and invent various devices that fall within the spirit and scope of the present invention. In addition, all conditional terms and embodiments listed herein are in principle clearly intended to be understood solely for the purpose of understanding the concept of the invention and are not to be limited to the specifically listed embodiments and states. do. In addition, it is to be understood that all detailed descriptions, including the principles, aspects, and embodiments of the present invention, as well as listing specific embodiments, are intended to include structural and functional equivalents of these matters. In addition, these equivalents should be understood to include not only equivalents now known, but also equivalents to be developed in the future, that is, all devices invented to perform the same function regardless of structure. Thus, for example, it should be understood that the block diagrams herein represent a conceptual view of example circuitry embodying the principles of the invention. Similarly, all flowcharts, state transitions, pseudocodes, and the like are understood to represent various processes performed by a computer or processor, whether or not the computer or processor is substantially illustrated on a computer readable medium and whether the computer or processor is clearly shown. Should be.

The functionality of the various elements shown in the figures, including functional blocks represented by a processor or similar concept, can be provided by the use of dedicated hardware as well as hardware capable of executing software in association with appropriate software. When provided by a processor, the functionality may be provided by a single dedicated processor, by a single shared processor or by a plurality of individual processors, some of which may be shared. In addition, the explicit use of the terms processor, control or similar terminology should not be interpreted exclusively as a citation of hardware capable of executing software, and is not intended to be used to store digital signal processor (DSP) hardware or software without limitation. It should be understood that it implicitly includes ROM, RAM, and non-volatile memory. Other hardware for the governor may also be included. Similarly, the switches shown in the figures may be presented conceptually only. It is to be understood that the action of such a switch can be performed manually or through the interaction of program control and dedicated logic via program logic or dedicated logic. Certain techniques may be selected by a designer with a more detailed understanding of the disclosure.

In the claims of this specification, components expressed as means for performing the functions described in the detailed description include all types of software including, for example, a combination of circuit elements or firmware / microcode, etc. that perform the functions. It is intended to include all methods of performing a function which are combined with appropriate circuitry for executing the software to perform the function. The invention, as defined by these claims, is equivalent to what is understood from this specification, as any means capable of providing such functionality, as the functionality provided by the various enumerated means are combined, and in any manner required by the claims. It should be understood that.

 The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. First, in adding reference numerals to the components of each drawing, it should be noted that the same components as much as possible even if displayed on different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

4 is a block diagram illustrating a DTV transmitter according to an embodiment of the present invention. As shown in the drawing, the transmitter 400 includes a first multiplexer 401, a data randomizer 403, and an RS encoder 405. Robust interleaver / packet formatter 407, data interleaver 409, enhanced encoder 411, robust data processor 413, trellis encoder 415, second multiplexer 417, and pilot inserter / modulator / RF converter 419.

According to the present invention, general data is mapped to a group represented by eight levels of {-7, -5, -3, -1, 1, 3, 5, 7}, and robust data is {-5, -3, 1, 7} or the technique to be mapped to any one of the two groups represented by the four levels of {-7, -1, 3, 5} is robust without impairing the technical idea of the present invention It can be combined with techniques that allow data to be mapped to groups represented by four different levels (eg {-7, -5, 5, 7} or {-7, -3, 3, 7}). In this case, other mapping of the signal path and the robust data encoding the robust data to be mapped to the mapping group ({-5, -3, 1, 7} or {-7, -1, 3, 5}) according to the present invention. Selection means for selecting any one of the signal paths to be encoded to be mapped to a group (e.g. {-7, -5, 5, 7} or {-7, -3, 3, 7}) do. Robust data can be mapped to one of two groups or represented by four levels of {-5, -3, 1, 7} or {-7, -1, 3, 5} depending on the selected signal path It may be mapped to a group represented by four levels (for example, {-7, -5, 5, 7} or {-7, -3, 3, 7}).

The data randomizer 403, RS encoder 405, data interleaver 409, trellis encoder 415, second multiplexer 417 and pilot inserter / modulator / RF converter 419 shown in FIG. The conventional data randomizer 101, RS encoder 103, data interleaver 105, trellis encoder 107, multiplexer 109, pilot inserter 111, VSB modulator 113 and RF, respectively. Same as transducer 115.

The first multiplexer 401 converts the general data packet 421 and the 4 level ({-5, -3, 1, 7} or {-7, -1, 3, 5}) symbols to be converted into 8 level symbols. The robust data packet 423 to be multiplexed under the control of the robust data flag signal 425.

The generic data packet 421 and the robust data packet 423 have the same attributes as a serial data stream consisting of 188 bytes of MPEG compatible data packet, while the robust data packet includes an information packet and a null packet. A null packet is a packet consisting of any data (eg, "0") with a null packet header that is inserted to secure packet space to be expanded according to the coding rate of robust data. In the present specification, a description will be made based on an embodiment in which a coding rate of robust data is 1/2, but it should be understood that the present invention is not limited to a coding rate of 1/2.

The robust data flag signal 425 is an external device (not shown) according to the ratio information (NRP, Equation 1) of the robust data and the general data in one field and the coding ratio information (1/2 or 1/4) of the robust data. The other component of the transmitting apparatus 400 including the first multiplexer 401 as a signal generated from the second multiplexer 401 may use the robust data flag signal 425 to determine whether the data currently being processed is a robust data packet.

The first multiplexer 401 multiplexes the general data packet 421, the robust data packet 423, and the robust data flag 425 according to the number of robust data packets per field. As an example, the position of the robust data packet may be defined as shown in Equation 1 according to the number thereof.

0 NRP/2 39 :

0 NRP / 2 39:

s

156){s | s = 4i, i = 0, 1,... , NRP-1}, (0

s

156)

NRP/2

78 :40

NRP / 2

78:

{s | s = 4i, i = 0, 1,... , 77} U {s | s = 4i + 2, i = 0, 1,... , NRP-79}

NRP/2

117 :79

NRP / 2

117:

{s | s = 4i, i = 0, 1,... , 77} U {s | s = 4i + 2, i = 0, 1,... , 77} U {s | s = 4i + 1, i = 0, 1,... , NRP-157}

NRP/2

156 :118

NRP / 2

156:

{s | s = 4i, i = 0, 1,... , 77} U {s | s = 4i + 2, i = 0, 1,... , 77} U {s | s = 4i + 1, i = 0, 1,... , 77} U {s | s = 4i, i = 0, 1,... , NRP-235}

In Equation 1, NRP is the number of robust segments occupied by robust data packets per data field, that is, the number of robust data packets in a frame, as described above, and an information packet and a null packet. It is a value including all the numbers and has a range of 0 to 312. Further, "U" means two sets of unions, s means data segment number in the data field, and has a range of 0 to 311.

Another embodiment of determining the location of a robust data packet can be defined as Equation (2).

RPI = 312 / NRP

RPP = floor (RPI x r)

In Equation 2, RPI is a robust data packet interval, and RPP is a robust data packet position. floor (*) represents a decimal cutting operation (rounding off to a decimal point) for converting an arbitrary number * to an integer value. r represents the arbitrary integer of 0-NRP.

According to Equation 2, when the NRP is 162 and the robust data coding ratio is 1/2, the positions of the general data and the robust data in the data field are determined as shown in Table 1 below.

Packet number Packet type 0 Tenacity One Null 2 Normal 3 Tenacity 4 Normal 5 Null 6 Normal 7 Tenacity 8 Normal 9 Null 10 Normal 11 Tenacity 12 Normal 13 Null 14 Normal 15 Tenacity ... ... 297 Normal 298 Tenacity 299 Normal 300 Null 301 Normal 302 Tenacity 303 Normal 304 Null 305 Normal 306 Tenacity 307 Normal 308 Null 309 Normal 310 Null 311 Normal

The general data packet 421 and the robust data packet 423 multiplexed on a packet basis in the first multiplexer 401 are randomized in the data randomizer 403, and each packet is 20 for FEC in the RS encoder 405. It is encoded to include parity information of bytes. In RS encoder 405, 20 RS parity bytes for FEC are added to 187 bytes of data to generate a total of 207 bytes of data transmitted per data segment. The robust data flag is not subjected to randomization and RS encoding. When 20 RS parity bytes are added by RS encoding for a robust data packet, a robust data flag is also displayed for the added RS parity bytes.

Next, the RS-coded generic / strong data packets contained in consecutive segments of each data field are input to the robust interleaver / packet formatter 407 and interleaved only for robust data (information packets) based on the robust data flag. The interleaved robust data is reconstructed into packets of 207 bytes according to the robust data coding rate, and the reconstructed robust data packets are multiplexed with normal data packets. Normal data packets have a certain delay to be multiplexed with robust data packets.

FIG. 5 is a block diagram illustrating the robust interleaver / packet formatter of FIG. 4. As shown in FIG. 5, the robust interleaver / packet formatter 407 includes a robust data interleaver 501, a packet formatter 503, and a third multiplexer. 505.

The robust data interleaver 501 interleaves only robust data packets according to the robust data flag signal. FIG. 6 is a conceptual diagram illustrating the robust data interleaver of FIG. 5. As shown in the drawing, the robust data interleaver 501 signals only the strong data packets among the data packets input from the RS encoder 405 in byte units. It receives the input and performs interleaving to transmit robust data to the packet formatter 503. In addition, the robust data interleaver 501 has parameters of M = 3, B = 69, and N = 207 to perform interleaving by inputting 1 byte from up to 69 different packets, and among the robust data packets in the interleaving process. Null packets are discarded and interleaving is performed only on the information packets.

The packet formatter 503 shown in FIG. 5 processes the robust data interleaved by the robust data interleaver 501. The packet formatter 503 receives 184 bytes from the robust data interleaver 501 and then generates two 207-byte data blocks for the 184 byte robust data. Here, four bits, e.g., LSBs (6, 4, 2, 0), in each byte of the generated 207-byte data block correspond to the input robust data. The remaining four bits, for example MSB (7, 5, 3, 1), are set to arbitrary values. On the other hand, in each of the generated 207-byte data blocks, the byte position which does not correspond to the 184-byte robust data is inserted with header byte data and arbitrary information data for RS parity bytes described later.

Next, the packet formatter 503 inserts a header corresponding to a null packet in the first 3 bytes of each generated 207 byte data block. The packet formatter 503 then generates a packet of 207 bytes by inserting 20 bytes of arbitrary information (e.g., "0") into each data block. As described below, the robust data processor 413 replaces the 20 bytes of arbitrary information with RS parity information.

All other remaining byte positions may be filled with bytes of 184 byte robust data in order. The packet formatter 503 checks whether the position corresponds to the parity byte position before inserting a robust data byte into each of the newly created 207 byte data blocks. If the position does not correspond to the position of the parity byte, then the robust data byte is placed in that position. If the position corresponds to a parity byte position, the byte position is skipped and the next byte position is checked. This process is repeated until all robust data bytes are arranged in a newly created 207 byte data block.

Thus, when robust interleaved four packets (4 x 207 bytes) of robust data are input to the packet formatter 503, the packet formatter 503 is composed of nine pieces of random information data bytes for robust data bytes, header bytes and RS parity bytes. Output a packet (9 x 207 bytes). Each of the nine packets output includes 92 bytes of robust data input to the packet formatter 503.

On the other hand, the position of the arbitrary information data byte for the RS parity byte for each packet is determined according to equation (3).

m = (52 x n + (s mod 52)) mod 207

Where m is the output byte number, that is, the parity byte position of the packet extended to 207 bytes, n (= 0 to 206) is the input byte, that is, the byte number of each packet, and s (= 0 to 311) is one data Indicates a segment corresponding to robust data in the field, that is, a packet number. The parity byte position, i.e. m, can be computed for n = 187-206 million only so that the position of 20 parity packets for each packet can always correspond to the last 20 bytes of the packet (this value of n is the last 20 of the packet). Corresponding to a byte).

For example, if you assign k = 0 and n = 187 to 206, then the parity byte positions for packet 0 are 202, 47, 99, 151, 203, 48, 100, 152, 204, 49, 101, 153, 205, 50, 102, 154, 206, 51, 103, 155. This means that the parity byte position after the interleaving of the data interleaver 411 becomes a packet 187 to 206 only when the parity byte position is the 202th byte. Similarly, another parity byte position should be the 47th byte. However, according to Equation 3, the parity byte may be located at the packet header byte position. M may be 0, 1 and / or 2. Therefore, to avoid the situation where the parity byte is located at the packet header byte position, the range of n may be increased by the number of parity bytes (maximum 3) at the header position. Accordingly, in the process of calculating the 20 m values, if the result of s mod 52 is any one of 1 to 7, some of the 20 m values are 0, 1, and / or 2.

For example, when s mod 52 = 0, all 20 m values do not represent the position (0, 1, or 2) of the header byte, and thus all 20 m values may be used as parity byte positions.

On the other hand, when s mod 52 = 1, one of the 20 m values is 0 (header byte position), in which case the n range is increased by 1 to be 186 to 206. Thus, twenty-one m values are computed and m values coming in header byte positions are discarded. The remaining 20 m values are specified as parity byte positions.

Similarly, if s mod 52 = 2, two of the 20 m values are 0 and 1 (header byte position), in which case the n range is increased by 2 to be 185 to 206. Thus, 22 m values are calculated and the m values, which are header byte positions (0 or 1), are discarded. The remaining 20 m values are specified as parity byte positions.

Table 2 shows the range of n according to position in the robust data segment.

s mod 52 M number additionally required range of n 0 0 187-206 One One 186-206 2 2 185-206 3 3 184-206 4 3 184-206 5 3 184-206 6 2 185-206 7 One 186-206 8 to 51 0 187-206

The third multiplexer 505 of FIG. 5 multiplexes the robust data packet and the general data packet output from the packet formatter 503 according to the robust data flag. The operation of the third multiplexer 505 is the same as the operation of the first multiplexer 401.

Referring back to FIG. 4, the data interleaver 409 reconstructs data packets in successive segments of each data field to scramble the sequential order of the robust data flag and the normal / strong data stream in accordance with the ATSC A / 53 standard. The interleaved byte unit outputs scrambled data. The structure of the data interleaver 409 has a structure similar to that of the robust data interleaver 501 (see Fig. 6, M = 4, B = 52, N = 208).

FIG. 7 is a diagram showing the structure of the reinforcement encoder of FIG. 4 in detail. As shown in the drawing, a plurality of reinforcement encoders 411 are specifically configured in parallel with, for example, 12 identical reinforcement encoders 411a to 411l. . Enhancement encoder 411 trellis interleaves the interleaved general / robust data and the robust data flag and codes the general / strong data based on the trellis interleaved robust data flag. As for general / strong data output from the data interleaver 409, 12 enhanced encoders 411a to 411l are sequentially input in byte units, and 2 bits of general / strong data of 2 bits (X ₁ ′, X ₂ ′) are input. Code as general / strong data symbols represented by (X ₁ , X ₂ ). For example, the input bit X ₂ ′ is an MSB (7, 5, 3, 1) code word, and the bit X ₁ ′ is an LSB (6, 4, 2, 0) code word. As described above, the MSBs (7, 5, 3, 1) and LSBs (6, 4, 2, 0) of the general data all contain information data, but the LSBs (6, 4, 2, 0) contains information data and MSBs (7, 5, 3, 1) contain arbitrary values.

Among the data symbols coded by the enhanced encoder 411, the general data symbols are input to the trellis encoder 415 by bypassing the robust data processor 413, and the robust data symbols are passed through the robust data processor 413. It is input to the release encoder 415. In this process, data symbols coded by each of the twelve enhanced encoders 411a to 411l are sequentially input to the trellis encoder 415 or the robust data processor 413 to perform trellis interleaving as a whole.

Referring again to FIG. 4, trellis encoder 415 is identical to trellis encoder as currently defined in the ATSC A / 53 standard. Although not shown in the figure, similarly to the case of the enhanced encoder 411, a plurality of trellis encoders 415, for example, 12 identical trellis encoders 415a to 415l are configured in parallel. Toughness input to the trellis encoder 415 via the robust data processor 413 by bypassing the robust data processor 413 and the general data symbols X ₁ , X ₂ input to the trellis encoder 415. The data symbols X ₁ and X ₂ are input to 12 trellis encoders 415a to 415l, and the trellis encoder 415 converts the input symbols X ₁ and X ₂ into 8 levels (general data). In this case, trellis encoding is performed using symbols of {-7, -5, -3, -1, 1, 3, 5, 7}) or 4 levels (strong data). 8 levels (general data) or 4 levels ({-5, -3, 1, 7} or {-7, -1, encoded for robust data) encoded by each of the 12 trellis encoders 415a through 415l. 3, 5}) are sequentially input to the second multiplexer 417 to perform trellis interleaving as a whole.

FIG. 8 is a conceptual diagram of an embodiment of the enhanced encoder and trellis encoder of FIG. 4 for explaining a process in which general data is output as 8-level symbols and robust data is output as 4-level symbols. As described below, since the robust data processor 413 processes only robust data but is independent of the process of outputting an 8 or 4 level symbol, Fig. 8 shows the enhanced encoder # 0 411a and trellis. Illustratively illustrates the conceptual connection relationship of encoder # 0 415a.

As defined in the current ATSC A / 53 standard, trellis encoder 415 includes a pre-coding block, a trellis encoding block and a symbol mapping block. The precoding block and trellis encoding block include registers D ₁ , D ₂ , D ₃ that store symbol delay values (eg, 12 symbol delay values).

Enhancement encoder # 0 (411a) codes the 2 bits (X ₁ ′, X ₂ ′) of general / strong data input from data interleaver 409 into 2 bits (X ₁ , X ₂ ) of general / strong data symbols. , Trellis encoder # 0 (415a) has eight levels (general) according to trellis encoded symbols (Z ₀ , Z ₁ , Z ₂ ) corresponding to two bits (X ₁ , X ₂ ) normal / strong data symbols. {-7, -5, -3, -1, 1, 3, 5, 7} for data or 4 levels ({-5, -3, 1, 7} or {-7 for robust data) , -1, 3, 5}) signals are output to the second multiplexer 417.

9 through 11 are detailed block diagrams illustrating the enhanced encoder of FIG. 4, and FIG. 9 shows four levels of {-5, -3, 1, 7} for data in which the trellis encoder 415 is robust. A reinforcement encoder that codes with 2 bits (X ₁ , X ₂ ) normal / strong data symbols to output a signal, and FIG. 10 shows that the trellis encoder 415 is {-7, -1, 3, 5 for robust data; } Is a reinforcement encoder that codes with two bits (X ₁ , X ₂ ) normal / strong data symbols to output a four-level signal of < RTI ID = 0.0 &_gt;.≪ / _RTI > A reinforcement encoder that codes into two bits (X ₁ , X ₂ ) normal / strong data symbols to output a 4-level signal of -3, 1, 7} or {-7, -1, 3, 5}.

Some multiplexers included in the enhanced encoder 411 receive general data and robust data and output general data or robust data according to the robust data flag.

In the case of the embodiment shown in Figs. 9 to 11 as well as the other embodiments shown in Figs. 12 to 15, trellis encoding is performed on X ₁ '(LSB) and X ₂ ' (MSB), which are input values of general data. The outputs of the block are Z ₀ = D ₃ , Z ₁ = X ₁ ', Z ₂ = (X ₂ ' XOR D ₁ ), and the symbol mapping block consists of trellis-encoded symbols (Z ₀ , Z ₁ , Z ₂ ) Outputs an eight-level signal of {-7, -5, -3, -1, 1, 3, 5, 7} to the second multiplexer 417.

As shown in FIG. 9, an exemplary enhancement encoder 411 may be largely divided into a first block 901, a second block 903, and a third block 905.

The first block 901 used for normal / strong data predicts Z ₀ , which is the output bit of the trellis encoding block, using X ₁ , which is the immediately preceding output bit of the enhancement encoder 411, and the trellis encoding block. Contains registers D ₂ and D ₃ . Accordingly, when the registers D ₂ and D ₃ of the trellis encoding block are directly used, the first block 901 may be omitted. Such an embodiment is illustrated in FIGS. 12 to 15.

The second block 903 to be used for the robust data are Claim 1 Z ₀ prediction value of the block (901) (D ₃₎ or a trellis encoding block in the register (D ₃₎ a Z ₁ value by using a value Z ₂ value This is a block to decide whether to set the same value as or inverted.

In the second block 903 of FIG. 9, when the Z ₀ predicted value D ₃ of the first block 901 or the register D ₃ of the trellis encoding block is zero, Z ₁ is inverted. _{If the} value of Z ₀ predicted value D ₃ of the first block 901 or the register D ₃ of the trellis encoding block is one (1), the value of Z ₁ becomes Z ₂ . That is, X ₁ = inverted X ₁ '(D ₃ = 0) or X ₁ = X ₁ ' (D ₃ = 1). Finally, the output signal level of the trellis encoder 415 is mapped to {-5, -3, 1, 7}.

In the second block 1003 of FIG. 10, if the Z ₀ predicted value D ₃ of the first block 901 or the register D ₃ of the trellis encoding block is one, the Z ₁ value is inverted. _{If the} value of Z ₀ predicted value D ₃ of the first block 901 or the register D ₃ of the trellis encoding block is zero, the value of Z ₁ becomes Z ₂ . That is, X ₁ = inverted X ₁ '(D ₃ = 1) or X ₁ = X ₁ ' (D ₃ = 0). Finally, the output signal level of the trellis encoder 415 is mapped to {-7, -1, 3, 5}.

In the second block 1103 of FIG. 11, the Z ₀ predicted value D ₃ of the first block 901 or the register D ₃ of the trellis encoding block may be selectively set to one (1) or the like by the level selection signal. By zero, the output signal level of the trellis encoder 415 is optionally mapped to {-5, -3, 1, 7} or {-7, -1, 3, 5}. In one embodiment. For example, if the output signal level of the trellis encoder 415 is mapped to {-5, -3, 1, 7} with respect to the current robust data, the level selection signal may be trellis encoder (for the next robust data). The output signal level of 415 may be selected to be mapped to {-7, -1, 3, 5}, or may be selected at any period. An embodiment of the Z ₀ predicted value D ₃ and the level selection signal applicable to the multiplexer of the second block 1103 is shown in FIG. 16.

The third block 905 used for the general / robust data is a block for canceling the pre-coded block with respect to the robust data of the trellis encoder 415, and is applied to X ₁ '(LSB) which is an input value of the robust data. We cancel the precoding block so that the output of the trellis encoding block is Z ₂ = X ₁ '. The third block includes the register D ₁ included in the precoding block of the trellis encoder 415. Therefore, when using the value of the register D ₁ included in the pre-coding block directly, the register D ₁ can be omitted. Such an embodiment is illustrated in FIGS. 12 to 15. The third block 905 receives X ₂ '(MSB) of general data and X ₁ ' (LSB) of robust data. As described above, X ₁ in the robust data '(LSB) may include information data X _2' (MSB) is X ₂ '(MSB) of robust data because it contains the random value is not used.

For example, when dividing the flow of time into time0, time1, and time2, the output values of the enhanced encoder 411 X ₁ , X ₂ , and the trellis encoder 415 according to the flow of time Z ₂ , Z ₁ , Z The relationship between ₀ and the register values D ₁ , D ₂ , and D ₃ is as shown in Equations 4 and 5 below.

Z ₂ | _time1 = D ₁ | _time0 XOR X ₂ | _time1 = D ₁ | _time1

Z ₁ | _time1 = X ₁ | _time1

Z ₀ | _time1 = D ₃ | _time0 = D ₂ | _time1

D ₃ | _time1 = D ₂ | _time0 XOR X ₁ | _time1

Z ₀ | _time2 = D ₃ | _time1

That is, the current output bit Z ₀ is the last register value D ₃ , which is predicted by the last bit X ₁ .

X ₁ '(LSB), Z ₀ prediction value (Z ₀ * = immediately before D ₃ ), X ₁ , Z ₂ , Z ₁ , Z ₀ and symbol level of robust data according to one embodiment shown in FIGS. 9 and 13 Is shown in Table 3 below.

X ₁ '' Z ₀ * X ₁ Z ₂ Z ₁ Z ₀ Symbol level 0 0 One 0 One 0 -3 One 0 0 One 0 0 One 0 0 One 0 One 0 -3 One 0 0 One 0 0 One 0 One 0 0 0 One -5 One One One One One One 7 0 One 0 0 0 One -5 One One One One One One 7

X ₁ '(LSB), Z ₀ prediction value (Z ₀ * = immediately before D ₃ ), X ₁ , Z ₂ , Z ₁ , Z ₀ and symbol level of robust data according to one embodiment shown in FIGS. 10 and 14 Is shown in Table 4 below.

X ₁ '' Z ₀ * X ₁ Z ₂ Z ₁ Z ₀ Symbol level 0 0 0 0 0 0 -7 One 0 One One One 0 5 0 0 0 0 0 0 -7 One 0 One One One 0 5 0 One One 0 One One -One One One 0 One 0 One 3 0 One One 0 One One -One One One 0 One 0 One 3

Referring back to FIG. 4, the robust data processor 413 is a component for preventing wrong recovery of robust data in a receiver according to the 8-VSB scheme, and is backward compatible with a receiver according to the 8-VSB scheme. Backward Compatibility). Therefore, when the receiver according to the 4-VSB scheme according to the embodiment of the present invention is used, a robust data processor 413 which provides backward compatibility is unnecessary. The magnitude or signal processing of a signal processed by a transmitter that does not provide backward compatibility may be different from the magnitude or signal processing of a signal processed by a transmitter that provides backward compatibility. For example, the packet formatter 503 of a transmitter that does not provide backward compatibility receives 207 bytes from the robust data interleaver 501 to process data and from the enhanced encoder 411 of the transmitter that does not provide backward compatibility. The output robust data is input to the trellis encoder 415 only after trellis deinterleaving is performed without passing through the robust data processor 413. However, as will be described below, it will be apparent to those skilled in the art that the present invention is applicable whether or not the transmitter provides backward compatibility. Therefore, it should be understood that the transmission apparatus according to the embodiment of the present invention is not limited to the embodiment providing backward compatibility.

17 is a detailed block diagram of the robust data processor of FIG. As shown in the figure, the robust data processor 413 includes a trellis deinterleaver 1701, a data deinterleaver 1703, an RS encoder 1705, and a data interleaver 1707. The robust data (X ₁ , X ₂ ) and the robust data flag output from the enhanced encoder 411 are trellis deinterleaved and data deinterleaved by the trellis deinterleaver 1701 and the data deinterleaver 1703 to form a packet. To be recombined.

As described above, 20 bytes of arbitrary information are inserted into the 207-byte data block generated by the packet formatter 503, and the RS encoder 1705 replaces the 20 bytes of arbitrary information with RS parity information. The robust data packet with the RS parity information inserted is interleaved in the data interleaver 1707 and output to the trellis encoder 415 in units of bytes.

Referring back to FIG. 4, the general data of the eight-level symbol and the robust data of the four-level symbol are segment sync and field sync synchronization bits from a synchronization unit (not shown) in the second multiplexer 417. Combined with the sequence, it is created as a data frame for transmission. The pilot signal is then inserted at the pilot inserter. The symbol stream is VSB suppressed carrier modulated in a VSB modulator. The baseband 8-VSB / 4-VSB symbol stream is finally converted into a radio frequency signal by the RF converter and transmitted.

18 is a view showing field sync segments of a data frame transmitted by the transmitting apparatus 400 of FIG. 4 according to the present invention. As shown in the figure, the segment transmitted by the transmitter 400 is basically the same as the segment of the ATSC A / 53 standard. However, in the reserved area corresponding to the last 104 symbols of the segment, 92 symbols except for the precode 12 symbols include information for recovering a robust data packet. The information for recovering the robust data packet includes ratio information of the robust data and the general data in one field (NRP, Equation 1) and coding ratio information (1/2 or 1/4) of the robust data. As will be described later, a receiving apparatus according to an embodiment of the present invention generates a robust data flag from information for restoring a robust data packet, and the component of the receiving apparatus uses the robust data flag to robust the current data. You can check whether it is a data packet.

19 is a block diagram showing a DTV receiver according to an embodiment of the present invention. As shown in the drawing, the receiver 1900 includes a tuner 1901, an IF filter and a detector 1903, and an NTSC cancellation filter 1905. ), Equalizer 1907, trellis decoder 1909, data deinterleaver 1911, packet formatter / robust deinterleaver 1913, RS decoder 1915, data derandomizer 1917, demultiplexer (1919) And a sync and timing recovery block 1921, a field sync decoder 1923, and a controller 1925.

According to the present invention, the general data transmitted by mapping to a group represented by eight levels of {-7, -5, -3, -1, 1, 3, 5, 7} is decoded and {-5, -3, The technique of decoding robust data transmitted by mapping to any one of two groups represented by four levels of 1, 7} or {-7, -1, 3, 5} is a technical idea of the present invention. Decode robust data transmitted by mapping to groups represented by the other four levels (e.g. {-7, -5, 5, 7} or {-7, -3, 3, 7}) without being compromised It can be combined with the technique. In this case, signal paths and other mapping groups which are mapped to mapping groups ({-5, -3, 1, 7} or {-7, -1, 3, 5}) according to the present invention to decode the transmitted robust data. (E.g., {-7, -5, 5, 7} or {-7, -3, 3, 7}) to select one of the signal paths that is mapped to decode the transmitted robust data Means may be further included. Robust data can be decoded according to the selected signal path.

Here, the decoded signal path may be a signal path that is only functionally separated. For example, as described below, the equalizer 1907 equalizes the received signal based on the robust data flag. In the robust data flag, the data to be processed is transmitted as general data, mapped to the mapping group ({-5, -3, 1, 7} or {-7, -1, 3, 5}) according to the present invention. And information identifying whether any of the robust data transmitted by mapping to another mapping group (for example, {-7, -5, 5, 7} or {-7, -3, 3, 7}) is transmitted. As for the conventional data signal, the signal level is determined at 8 levels of {-7, -5, -3, -1, 1, 3, 5, 7} as in the conventional case. The signal level is determined for the four levels of any one of the mapping groups ({-5, -3, 1, 7} or {-7, -1, 3, 5}) or represented by the other four levels. The signal level can be determined for four levels of any one of the groups (eg {-7, -5, 5, 7} or {-7, -3, 3, 7}). Similarly, the trellis decoder 1909 trellis for 8 levels of {-7, -5, -3, -1, 1, 3, 5, 7} as for the conventional data signal. Decoding is performed, and for robust data signals, four levels of any one of the mapping groups ({-5, -3, 1, 7} or {-7, -1, 3, 5}) according to the present invention are performed. Four levels of one of the groups trellis decoded or represented by four different levels (e.g. {-7, -5, 5, 7} or {-7, -3, 3, 7}) Trellis decode for.

The tuner 1901, IF filter and detector 1903, NTSC cancellation filter 1905, data deinterleaver 1911, RS decoder 1915, and synchronization and timing recovery block 1921 shown in FIG. It performs the same functions as tuner 201, IF filter and detector 203, NTSC cancellation filter 205, data deinterleaver 211, RS decoder 213 and sync and timing recovery block 215.

The four level robust data signal of {-5, -3, 1, 7} or {-7, -1, 3, 5} used in the receiver 1900 is a four level robust data used in the transmitter 400. Depends on the type of signal.

The field synchronization decoder 1923 receives the segment of the data frame shown in Fig. 18, and performs robust data packet reconstruction information in the reserved area (ratio information of robust data and general data in one field and coding ratio information of robust data). And the like) to the control unit 1925.

20 is a detailed block diagram illustrating the control unit of FIG. 19. As shown in the figure, the controller 1925 includes a general / strong data classification flag generator 2001, a data interleaver 2003, a trellis interleaver 2005, a delay buffer 2007, and a delay operator 2009. .

The general / robust data classification flag generator 2001 generates the robust data flag using the robust data packet recovery information received from the field sync decoder 1923.

The generated robust data flag is bitwise data interleaving and trellis interleaving according to ATSC A / 53 in the data interleaver 2003 and the trellis interleaver 2005, respectively, so that the equalizer 1907 and the trellis decoder 1909 are performed. Is sent). Since the robust data flag included in the data frame transmitted from the transmitting device 400 is already interleaved with data interleaving and trellis interleaved, the equalizer 1907 and trellis decoder 1909 have data interleaving and trellis interleaving. Equalization and trellis decoding are performed based on the determined robust data flags.

Meanwhile, the delay buffer 2007 receives the robust data flag generated by the general / strong data classification flag generator 2001 and then processes the data in the trellis decoder 1909 and the data deinterleaver 1911. The robust data flag is transmitted to the packet formatter / strong deinterleaver 1913 in consideration of the delay that occurs. The delay buffer 2007 also adds robust data flags to the data de-randomizer 1917, demultiplexer 1919, and delay operator 2009, taking into account the delay that occurs as the data is processed by the packet formatter / robust deinterleaver 1913. Transmit each).

The delay operator 2009 receives a robust data flag and a field sync decoder 1923 considering delays for general data generated by processing the robust data in the packet formatter / robust deinterleaver 1913 received from the delay buffer 2007. The delay time of the robust data packet is calculated by using the robust data packet recovery information received from the Rx, and is transmitted to the data de-randomizer 1917. The data de-randomizer 1917 performs de-randomization in synchronization with a field sync signal of the data frame, and the robust data packet restoration information received from the field sync decoder 1923 includes a data packet of robust data packet in the data frame. Information about the location is included. However, in the packet formatter / robust deinterleaver 1913, data processing is performed only for the robust data packet, and in particular, the deinterleaving process performed in the robust deinterleaver 2103 (see FIGS. 21 and 22) is about several packets for the robust data packet. Causes a delay. The delay operator 2009 calculates a delay time for the robust data packet based on the received robust data packet restoration information and the robust data flag to compensate for the delay for the robust data packet and transmits the delay time to the data derandomizer 1917. do. The data derandomizer 1917 performs derandomizing on the general data packet and the robust data packet based on the received robust data flag and the delay time for the robust data packet. For example, if after performing de-randomizing on the nth general data packet, the strong data packet that the next de-randomizing should be received is not a strong data packet sent by the transmitter from the n + 1th, but k (k <n) may be the strongest data packet sent. The reason why the robust data packet delay for the general data packet is large is that a delay in recovering the original packet from the packet formatter / strong deinterleaver 1913 is included. Therefore, the data derandomizer 1917 should perform derandomizing in consideration of this delay.

FIG. 21 is a block diagram showing the packet formatter / robust deinterleaver of FIG. 19, and FIG. 22 is a conceptual diagram showing the robust data deinterleaver of FIG. 21. The robust interleaver / packet formatter of the transmitter 400 shown in FIG. (407) Perform an operation opposite to the operation. That is, a robust data packet containing information data by removing the RS parity byte (20 bytes) and the header byte (3 bytes) included in the robust data segment (207 bytes) input from the data deinterleaver 1911 and null Create a packet. Therefore, when a robust data segment of nine packets (9 x 207 bytes) is input to the packet formatter 2011, the packet formatter 2011 outputs four robust data packets composed of information data and five null packets composed of null data. do. Next, the robust data deinterleaver 2103 receives the robust data packet input from the packet formatter 2011 in units of bytes and performs deinterleaving to transmit the robust data packet to the multiplexer 2105. In the deinterleaving process, null packets of robust data packets are discarded and deinterleaving is performed only on information packets. Normal data packets have a certain delay to be multiplexed with robust data packets.

Multiplexed generic data packets and robust data packets are sent to the RS decoder 1915. The RS decoder 1915 RS-decodes each packet and transmits the decoded data to the data derandomizer 1917.

Referring back to FIG. 19, the demultiplexer 1919 demultiplexes the normal data packet and the robust data packet according to the robust data flag and outputs them as a serial data stream consisting of 188 bytes of MPEG compatible data packets.

The equalizer 1907 may be a known determiner known as a slicer or a trellis decoder with a trace back of zero. The equalizer 1907 performs equalization on the received signal based on bit data interleaving transmitted from the controller 1925 and trellis interleaving according to ATSC A / 53. As for the conventional data signal, the signal level is determined at 8 levels of {-7, -5, -3, -1, 1, 3, 5, 7} as in the conventional case, and {-5 for a robust data signal. , -3, 1, 7} or 4 levels of {-7, -1, 3, 5} to determine the signal level. That is, for the robust data signal, decision data used for updating the tap coefficient of the equalizer 1907 is 4 of {-5, -3, 1, 7} or {-7, -1, 3, 5}. The level signal is used. For example, the trellis decoder used in the equalizer 1907 determines the signal level according to the state level based on the 4 level instead of the state level based on the conventional 8 level for the robust data signal. That is, since the signal level is determined by restricting some paths for robust data, accurate signal level determination is possible. Accurate signal level determination increases the convergence speed of the equalizer, resulting in improved reception for robust data as well as general data in a Doppler environment.

The trellis decoder 1909 may be a trellis decoder that conforms to the ATSC A / 53 standard, and similar to the trellis decoder that may be used in the equalizer 1907, for general data signals { Perform trellis decoding on 8 levels of -7, -5, -3, -1, 1, 3, 5, 7} and {-5, -3, 1, 7} or Perform trellis decoding on 4 levels of {-7, -1, 3, 5}. That is, the trellis decoder 1909 performs trellis decoding on the robust data signal according to the state diagram based on the four levels instead of the state diagram based on the conventional eight levels.

Since trellis decoding is performed by restricting some paths for robust data, accurate trellis decoding is possible. FIG. 23 is a state diagram based on the conventional eight levels, and FIG. 24 is a state diagram based on the four levels of {-7, -1, 3, 5} according to an embodiment of the present invention. As shown in the figure, according to the state diagram based on the conventional eight levels, when the current state may be "00" in the process of generating a symbol, the previous state is {-7}, {1} in "00". And the previous state is "-3" to {-3} and {5}. On the other hand, according to the state diagram based on the four levels of an embodiment of the present invention, when the current state may be "00" in the process of generating a symbol, the case where the previous state is "00" to {-7} and the previous state Is "10" to {5}, which is a total of two cases. As shown in an embodiment of the present invention, when trellis decoding is performed by restricting some paths for robust data, a free distance affecting trellis decoding capability increases.

According to an embodiment of the present invention, the 8-VSB receiving apparatus conforming to the ATSC A / 53 standard may receive a general data packet, and the robust data packet is treated as a null packet to provide backward compatibility.

25 is a graph comparing symbol average power (energy / symbol) of a conventional 4-VSB communication system and a 4-VSB communication system according to the present invention in a white Gaussian noise (AWGN) channel environment. -5, 5, 7} A graph comparing 4-VSB technology (black) with one embodiment of the present invention (white). The horizontal axis of the graph shown in the figure represents the percentage (%) of the robust data packets mixed with the general data packet and the vertical axis represents the symbol average power (energy / symbol). According to the conventional {-7, -5, 5, 7} 4-VSB technology, the symbol average power increases as the percentage (%) of the robust data packets mixed with the general data packets increases. On the other hand, according to one embodiment of the present invention, the symbol average power is not affected by the percentage of robust data packets mixed in the general data packet.

In addition, according to an embodiment of the present invention, the average power is 21 energy / symbol, and the average power for transmitting a symbol representing robust data is the same as the average power of the conventional 8-VSB scheme.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible in the technical field of the present invention without departing from the technical spirit of the present invention. It will be clear to those of ordinary knowledge.

As described above, according to the present invention, a dual stream composed of general data following the 8-VSB scheme and robust data following the specific 4-VSB scheme can be transmitted and received without increasing the average power regardless of the mixing ratio. In addition, the reception performance of the robust data as well as the general data is improved to lower the SNR satisfying the TOV.

Claims (45)

In a digital signal transmission system, Input means for receiving a digital video data stream; If the data stream contains robust data, any of two groups in which the robust data is represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} Encoding means for performing encoding on the robust data to be mapped to one group; And VSB transmission means for performing VSB modulation on the output signal of the encoding means to transmit to the VSB receiving system Digital signal transmission system comprising a. The method of claim 1, The digital video data stream Containing general data Digital signal transmission system. The method of claim 2, The encoding means When general data is included in the data stream, encoding is performed on the general data so that the general data is mapped to {-7, -5, -3, -1, 1, 3, 5, 7}. Digital signal transmission system. The method of claim 1, The encoding means An enhancement encoder for receiving the information data included in the data stream in units of 2 bits (X ₁ ′, X ₂ ′) and encoding the data data into data symbols represented by 2 bits (X ₁ , X ₂ ); And A trellis encoder that outputs a data symbol of any level among predetermined levels represented by three bits (Z ₂ , Z ₁ , Z ₀ ) based on the data symbols represented by the two bits (X ₁ , X ₂ ). Digital signal transmission system comprising a. The method of claim 4, wherein The enhanced encoder The information data bit (X) based on the Z ₀ predicted value so that the trellis encoder outputs a robust data symbol of any one of four levels of {-5, -3, 1, 7} as shown in Table 1 below. ₁ ') to encode the data symbol bits (X ₁ ) Digital signal transmission system. Table 1 X ₁ '' Z ₀ * X ₁ Z ₂ Z ₁ Z ₀ Symbol level 0 0 One 0 One 0 -3 One 0 0 One 0 0 One 0 0 One 0 One 0 -3 One 0 0 One 0 0 One 0 One 0 0 0 One -5 One One One One One One 7 0 One 0 0 0 One -5 One One One One One One 7 Where Z ₀ * is the Z ₀ prediction. The method of claim 4, wherein The enhanced encoder The information data bit (X) based on the Z ₀ prediction value so that the trellis encoder outputs a robust data symbol of any one of four levels of {-7, -1, 3, 5} as shown in Table 2 below. ₁ ') to encode the data symbol bits (X ₁ ) Digital signal transmission system. [Table 2] X ₁ '' Z ₀ * X ₁ Z ₂ Z ₁ Z ₀ Symbol level 0 0 0 0 0 0 -7 One 0 One One One 0 5 0 0 0 0 0 0 -7 One 0 One One One 0 5 0 One One 0 One One -One One One 0 One 0 One 3 0 One One 0 One One -One One One 0 One 0 One 3 Where Z ₀ * is the Z ₀ prediction. The method of claim 2, The input means when the digital data stream includes the general data and the robust data A multiplexer for multiplexing the general data and the robust data, The location of the robust data packet is defined according to Equation 1 below. Digital signal transmission system. [Equation 1] RPI = 312 / NRP RPP = floor (RPI x r) NRP is the number of robust data packets in the data frame transmitted by the digital signal transmission system, RPI is the robust data packet interval, and RPP is the robust data packet. Robust data packet position, floor (*) is the decimal cutting operation, and r is any integer from 0 to NRP. The method of claim 1, The encoding means Determination means for selectively determining which of two groups, {-5, -3, 1, 7} and {-7, -1, 3, 5}, as the group to which the robust data is to be mapped; Digital signal transmission system comprising a. In a digital signal transmission system, Input means for receiving a digital video data stream; When the data stream includes the robust data, any one of two groups in which the robust data is represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} First encoding means for performing encoding on the robust data to be mapped to one group; Second encoding means for performing encoding on the robust data such that the robust data is mapped to a group represented by four levels other than the two groups; Selection means for selectively inputting the robust data into any one of the first encoding means and the second encoding means; And VSB transmission means for performing VSB modulation on one of the first encoding means and the second encoding means to transmit to the VSB receiving system Digital signal transmission system comprising a. The method of claim 9, The digital video data stream Containing general data Digital signal transmission system. The method of claim 10, The first encoding means or the second encoding means When general data is included in the data stream, encoding is performed on the general data so that the general data is mapped to {-7, -5, -3, -1, 1, 3, 5, 7}. Digital signal transmission system. In a digital signal communication system, Transmitter; And Receiver Including but not limited to: The transmitter is Input means for receiving a digital video data stream; If the data stream contains robust data, any of two groups in which the robust data is represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} Encoding means for performing encoding on the robust data to be mapped to one group; And VSB transmitting means for performing VSB modulation on the output signal of the encoding means and transmitting to the receiving device Including, The receiving device Wireless receiving means for receiving a signal transmitted by the transmitter and converting the signal into a baseband signal; Equalizing means for determining a signal level of robust data based on any one of the two groups used by the transmitter; Trellis decoding means for trellis decoding robust data output from the equalizing means based on any one of the two groups used by the transmitter; And Decoding means for decoding the output signal of said trellis decoding means and outputting a digital video data stream; Digital signal communication system comprising a. The method of claim 12, The digital video data stream Containing general data Digital signal communication system. The method of claim 13, The encoding means When the general data is included in the data stream, encoding is performed on the general data so that the general data is mapped to {-7, -5, -3, -1, 1, 3, 5, 7}, The equalizing means is Determining a signal level of general data based on the {-7, -5, -3, -1, 1, 3, 5, 7}, The trellis decoding means Trellis decoding general data output from the equalizing means based on the {-7, -5, -3, -1, 1, 3, 5, 7} Digital signal communication system. The method of claim 12, The encoding means An enhancement encoder for receiving the information data included in the data stream in units of 2 bits (X ₁ ′, X ₂ ′) and encoding the data data into data symbols represented by 2 bits (X ₁ , X ₂ ); And A trellis encoder that outputs a data symbol of any level among predetermined levels represented by three bits (Z ₂ , Z ₁ , Z ₀ ) based on the data symbols represented by the two bits (X ₁ , X ₂ ). Digital signal communication system comprising a. The method of claim 15, The enhanced encoder The information data bit (X) based on the Z ₀ predicted value so that the trellis encoder outputs a robust data symbol of any one of four levels of {-5, -3, 1, 7} as shown in Table 3 below. ₁ ') to encode the data symbol bits (X ₁ ) Digital signal communication system. Table 3 X ₁ '' Z ₀ * X ₁ Z ₂ Z ₁ Z ₀ Symbol level 0 0 One 0 One 0 -3 One 0 0 One 0 0 One 0 0 One 0 One 0 -3 One 0 0 One 0 0 One 0 One 0 0 0 One -5 One One One One One One 7 0 One 0 0 0 One -5 One One One One One One 7 Where Z ₀ * is the Z ₀ prediction. The method of claim 15, The enhanced encoder The information data bit (X) based on the Z ₀ predicted value such that the trellis encoder outputs a robust data symbol of any one of four levels of {-7, -1, 3, 5} as shown in Table 4 below. ₁ ') to encode the data symbol bits (X ₁ ) Digital signal communication system. Table 4 X ₁ '' Z ₀ * X ₁ Z ₂ Z ₁ Z ₀ Symbol level 0 0 0 0 0 0 -7 One 0 One One One 0 5 0 0 0 0 0 0 -7 One 0 One One One 0 5 0 One One 0 One One -One One One 0 One 0 One 3 0 One One 0 One One -One One One 0 One 0 One 3 Where Z ₀ * is the Z ₀ prediction. The method of claim 13, The input means when the digital data stream includes the general data and the robust data A multiplexer for multiplexing the general data and the robust data, The location of the robust data packet is defined according to Equation 2 below. Digital signal communication system. [Equation 2] RPI = 312 / NRP RPP = floor (RPI x r) NRP is the number of robust data packets in the data frame transmitted from the transmitter, RPI is the robust data packet interval, and RPP is the location of the robust data packet. (Robust data Packet Position), floor (*) is a decimal cutting operation, r is an arbitrary integer from 0 to NRP. The method of claim 12, The encoding means Determination means for selectively determining which of two groups, {-5, -3, 1, 7} and {-7, -1, 3, 5}, as the group to which the robust data is to be mapped; Digital signal communication system comprising a. The method of claim 12, The encoding means A data randomizer for performing data randomization on the output signal of the input means; An RS encoder for performing Reed Solomon (RS) encoding on an output signal of the data randomizer; A robust interleaver / packet formatter which interleaves robust data among the output signals of the RS encoder and reconstructs the robust data packet according to the robust data coding ratio; And A data interleaver for performing data interleaving on the output signal of the robust interleaver / packet formatter Digital signal communication system further comprising. The method of claim 20, The decoding means A data deinterleaver for performing data deinterleaving on the signal output from the trellis decoding means; A packet formatter / robust deinterleaver for reconstructing a robust data packet composed of information data for robust data among the signals output from the data deinterleaver and performing data deinterleaving on the reconstructed robust data packet; An RS decoder for performing RS decoding on an output signal of the packet formatter / strong deinterleaver; A data de-randomizer for performing data de-randomization on the output signal of the RS decoder; And Demultiplexer for performing demultiplexing on the output signal of the data derandomizer Digital signal communication system comprising a. The method of claim 21, The receiving device A robust data flag generator for generating a robust data flag capable of confirming robust data based on the robust data recovery information included in the output signal of the radio receiving means; And Delay buffer for transmitting the robust data flag to the packet formatter / strong deinterleaver in consideration of the delay caused by processing the data in the data deinterleaver. Digital signal communication system further comprising. The method of claim 22, The delay buffer The robust data flag is further transmitted to the data de-randomizer in consideration of the delay caused by processing the data in the packet formatter / robust deinterleaver. Digital signal communication system. The method of claim 23, wherein If the digital image data stream includes the general data and the robust data, the receiving device Receiving the robust data flag considering the delay caused by processing the data in the packet formatter / robust deinterleaver from the delay buffer and receiving the robust data recovery information to calculate the delay time of robust data for the general data. A delay operator for transmitting to the data derandomizer Digital signal communication system further comprising. In a digital signal communication system, Transmitter; And Receiver Including but not limited to: The transmitter is Input means for receiving a digital video data stream; When the data stream includes the robust data, any one of two groups in which the robust data is represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} First encoding means for performing encoding on the robust data to be mapped to one group; Second encoding means for performing encoding on the robust data such that the robust data is mapped to a group represented by four levels other than the two groups; Selection means for selectively inputting the robust data into any one of the first encoding means and the second encoding means; And VSB transmission means for performing VSB modulation on one of the output signal of the first encoding means and the second encoding means to transmit to the receiving device Including, The receiving device Wireless receiving means for receiving a signal transmitted by the transmitter and converting the signal into a baseband signal; The transmission among two groups represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} and a group represented by four levels other than the two groups Equalizing means for determining a signal level of robust data based on any one of the groups used by the apparatus; The transmission among two groups represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} and a group represented by four levels other than the two groups Trellis decoding means for trellis decoding the robust data output from the equalizing means based on any one group used by the apparatus; And Decoding means for decoding the output signal of said trellis decoding means and outputting a digital video data stream; Digital signal communication system comprising a. The method of claim 25, The digital video data stream Containing general data Digital signal communication system. The method of claim 26, The first encoding means or the second encoding means When the general data is included in the data stream, encoding is performed on the general data so that the general data is mapped to {-7, -5, -3, -1, 1, 3, 5, 7}, The means for selecting Selectively inputting the general data into any one of the first encoding means and the second encoding means, The equalizing means is Determining a signal level of general data based on the {-7, -5, -3, -1, 1, 3, 5, 7}, The trellis decoding means Trellis decoding general data output from the equalizing means based on the {-7, -5, -3, -1, 1, 3, 5, 7} Digital signal communication system. In a digital signal receiving system, Wireless receiving means for receiving a signal including digital image data transmitted by a VSB transmission system and converting the signal into a baseband signal; Robust data mapped to any one of two groups represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} is added to the digital image data. Equalizing means for determining a signal level of said robust data based on any one of said two groups used by said VSB transmission system; Trellis decoding means for trellis decoding robust data output from the equalizing means based on one of the two groups used by the VSB transmission system; And Decoding means for decoding the output signal of said trellis decoding means and outputting a digital video data stream; Digital signal receiving system comprising a. The method of claim 28, The digital image data Containing general data Digital signal receiving system. The method of claim 29, The equalizing means is Determining a signal level of general data based on {-7, -5, -3, -1, 1, 3, 5, 7} used by the VSB transmission system, The trellis decoding means Trellis decoding general data output from the equalizing means based on {-7, -5, -3, -1, 1, 3, 5, 7} used by the VSB transmission system Digital signal receiving system. In a digital signal receiving system, Wireless receiving means for receiving a signal including digital image data transmitted by a VSB transmission system and converting the signal into a baseband signal; Mapped to two groups represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} and a group represented by four levels other than the two groups Equalizing means for determining a signal level of the robust data based on any one of the groups used by the VSB transmission system when the robust data is included in the digital video data; Trellis decoding means for trellis decoding robust data output from the equalizing means based on any one of the groups used by the VSB transmission system; And Decoding means for decoding the output signal of said trellis decoding means and outputting a digital video data stream; Digital signal receiving system comprising a. The method of claim 31, wherein The digital image data Containing general data Digital signal receiving system. 33. The method of claim 32, The equalizing means is Determining a signal level of general data based on {-7, -5, -3, -1, 1, 3, 5, 7} used by the VSB transmission system, The trellis decoding means Trellis decoding general data output from the equalizing means based on {-7, -5, -3, -1, 1, 3, 5, 7} used by the VSB transmission system Digital signal receiving system. In the digital signal transmission method, A first step of receiving a digital image data stream; If the data stream contains robust data, any of two groups in which the robust data is represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} Performing encoding on the robust data to be mapped to one group; And A third step of performing VSB modulation on the resultant signal of the second step to transmit to the VSB receiving system; Digital signal transmission method comprising a. The method of claim 34, wherein The digital video data stream Containing general data Digital signal transmission method. 36. The method of claim 35 wherein The second step is Performing encoding on the general data so that the general data is mapped to {-7, -5, -3, -1, 1, 3, 5, 7} when the general data is included in the data stream. Containing Digital signal transmission method. The method of claim 34, wherein The second step is A twenty-first step of receiving the information data included in the data stream in units of 2 bits (X ₁ ′, X ₂ ′) and encoding the data data into data symbols represented by 2 bits (X ₁ , X ₂ ); And A twenty-second step of outputting a data symbol of any level among predetermined levels represented by three bits (Z ₂ , Z ₁ , Z ₀ ) based on the data symbols represented by the two bits (X ₁ , X ₂ ); Digital signal transmission method comprising a. The method of claim 37, The 21st step According to the twenty-second step, as shown in Table 5 below, the information data bit (X) based on the Z ₀ prediction value is output to output a robust data symbol of any one of four levels of {-5, -3, 1, 7}. Encoding ₁ ') into the data symbol bits (X ₁ ). Digital signal transmission method. Table 5 X ₁ '' Z ₀ * X ₁ Z ₂ Z ₁ Z ₀ Symbol level 0 0 One 0 One 0 -3 One 0 0 One 0 0 One 0 0 One 0 One 0 -3 One 0 0 One 0 0 One 0 One 0 0 0 One -5 One One One One One One 7 0 One 0 0 0 One -5 One One One One One One 7 Where Z ₀ * is the Z ₀ prediction. The method of claim 37, The 21st step According to the twenty-second step, the information data bit (X) based on the Z ₀ prediction value is output to output a robust data symbol of any one of four levels of {-7, -1, 3, 5} as shown in Table 6 below. Encoding ₁ ') into the data symbol bits (X ₁ ). Digital signal transmission method. Table 6 X ₁ '' Z ₀ * X ₁ Z ₂ Z ₁ Z ₀ Symbol level 0 0 0 0 0 0 -7 One 0 One One One 0 5 0 0 0 0 0 0 -7 One 0 One One One 0 5 0 One One 0 One One -One One One 0 One 0 One 3 0 One One 0 One One -One One One 0 One 0 One 3 Where Z ₀ * is the Z ₀ prediction. In the digital signal communication method, Transmitting step; And Receive step Including but not limited to: The transmitting step A first step of receiving a digital image data stream; If the data stream contains robust data, any of two groups in which the robust data is represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} Performing encoding on the robust data to be mapped to one group; And A third step of performing VSB modulation on the resultant signal of the second step and transmitting the result; Including, The receiving step A fourth step of receiving the signal transmitted by the third step and converting the signal into a baseband signal; A fifth step of determining a signal level of robust data based on any one of the two groups used in the transmitting step; A sixth step of trellis decoding the robust data which is a result signal of the fifth step based on any one of the two groups used in the transmitting step; And A seventh step of decoding the result signal of the sixth step to output a digital video data stream; Digital signal communication method comprising a. The method of claim 40, The digital video data stream Containing general data Digital signal communication method. The method of claim 41, wherein The second step is Performing encoding on the general data so that the general data is mapped to {-7, -5, -3, -1, 1, 3, 5, 7} when the general data is included in the data stream. Including, The fifth step is Determining a signal level of general data based on the {-7, -5, -3, -1, 1, 3, 5, 7}, The sixth step Trellis decoding general data which is a result signal of the fifth step based on the {-7, -5, -3, -1, 1, 3, 5, 7} Digital signal communication method. In the digital signal receiving method, Receiving a signal including digital image data transmitted by a VSB transmission system and converting the signal into a baseband signal; Robust data mapped to any one of two groups represented by four levels of {-5, -3, 1, 7} and {-7, -1, 3, 5} is added to the digital image data. A second step of determining a signal level of the robust data based on any one of the two groups used by the VSB transmission system when included; A third step of trellis decoding the robust data which is a result signal of the second step based on any one of the two groups used by the VSB transmission system; And A fourth step of decoding the resultant signal of the third step to output a digital video data stream Digital signal receiving method comprising a. The method of claim 43, The digital image data Containing general data Digital signal reception method. The method of claim 44, The second step is Determining a signal level of general data based on {-7, -5, -3, -1, 1, 3, 5, 7} used by the VSB transmission system, The third step is Trellis decoding general data which is a result signal of the second step based on {-7, -5, -3, -1, 1, 3, 5, 7} used by the VSB transmission system; doing Digital signal reception method.

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