KR101079100B1 - digital broadcasting system, method, and data structure - Google Patents

Abstract

The present invention relates to digital broadcasting transmission / reception, and in particular, the present invention inserts and transmits predetermined known data known to the transmission / reception side at a specific position of a data area where enhanced data is transmitted, and at the reception side, By using the data in a demodulation or equalization process, the reception performance can be improved in an environment in which channel variation or noise is weak.

VSB, Base Data, Burst

Description

Digital broadcasting system, method, and data structure

1 is a block diagram of a general digital broadcast transmission system

2 is a view showing the structure of a typical VSB transmission frame

3 is a block diagram illustrating a multiplexing apparatus according to an embodiment of the present invention;

4A and 4B illustrate an example of a multiplexing method of the multiplexing apparatus of FIG. 3.

5 is a block diagram illustrating a digital broadcast transmission system according to an embodiment of the present invention.

6 is a block diagram illustrating a digital broadcast transmission system according to another embodiment of the present invention.

7 is a block diagram illustrating a digital broadcast receiving system according to an embodiment of the present invention.

Explanation of symbols for the main parts of the drawings

301: E-VSB preprocessor 302: E-VSB packet formatter

303: packet multiplexer 310: scheduler

700: receiver 800: burst controller

The present invention relates to a digital communication system, and more particularly, to a digital broadcasting system, a method, and a data structure that modulate in a VSB (Vestigial Side Band) scheme to transmit and receive the same.

In the United States, ATSC 8T-VSB transmission system was adopted as a standard in 1995 for terrestrial digital broadcasting, and broadcasted since the second half of 1998.In Korea, ATSC 8T-VSB transmission system, which is identical to the US method, was adopted as a standard in May 1995. Experimental broadcasting was started, and on August 31, 2000, the test broadcasting system was switched.

1 shows a conventional ATSC 8T-VSB transmission system. The data randomizer randomizes the input MPEG video / audio data, and the Reed-Soloron encoder adds 20 bytes of parity code by Reed-Solomon encoding the data, and the data interleaver interleaves the data, and the trellis encoder Converts the data from bytes into symbols and then trellis-codes them. The mux muxes the symbol strings and sync signals, the pilot inserter adds the pilot signal to the symbol strings, the VSB modulator modulates the symbol strings into an 8 VSB signal of the intermediate frequency band, and the RF converter converts the intermediate frequency signal into an RF band signal. Transmit and transmit through the antenna.

2 shows a general VSB transmission frame structure in which one frame consists of two fields and each field consists of one field sync segment and 312 data segments.

The 8T-VSB transmission system, adopted as a digital broadcasting standard in North America and Korea, is a system developed for transmission of MPEG video / audio data. However, with the rapid development of digital signal processing technology and the widespread use of the Internet, digital home appliances, computers, and the Internet are being integrated into one big framework. Therefore, in order to meet various needs of users, it is necessary to develop a system capable of transmitting various additional data in addition to video / audio data through a digital broadcasting channel.

Some users of supplementary data broadcasting are expected to use supplementary data broadcasting by using PC card or portable device equipped with simple indoor antenna. Due to the effects of ghosts and noise caused by reflected waves, broadcast reception performance may deteriorate. However, unlike the general video / audio data, the additional data transmission has to have a lower error rate. In the case of video / audio data, errors that the human eye and ears cannot detect are not a problem, while in the case of additional data (eg program executables, stock information, etc.), a bit error may cause serious problems. It may cause a problem. therefore There is a need to develop a system that is more resistant to ghosting and noise in the channel.

The transmission of additional data will usually be done in a time division manner over the same channel as the MPEG video / sound. Since the beginning of digital broadcasting, however, ATSC VSB digital broadcasting receivers that receive only MPEG video / audio have been widely used in the market. Therefore, additional data transmitted on the same channel as MPEG video / audio should not affect the existing ATSC VSB-only receivers that have been used in the market. Such a situation is defined as ATSC VSB compatible, and the additional data broadcasting system should be compatible with the ATSC VSB system. The additional data may also be referred to as enhanced data or EVSB data.

In addition, in a poor channel environment, the reception performance of the conventional ATSC VSB receiving system may be degraded. Especially in the case of portable and mobile receivers, robustness against channel changes and noise is required.

It is therefore an object of the present invention to provide a new digital communication system suitable for additional data transmission and resistant to noise.

Another object of the present invention is to provide a broadcast system, a method, and a data structure for improving reception performance by inserting and transmitting known data known to the transmitting / receiving side into a predetermined area of a data section.

It is still another object of the present invention to provide an apparatus, method, and data structure for time division multiplexing, transmitting and receiving enhanced data including main data and known data.

In order to achieve the above object, the present invention provides a field synchronization or a field synchronization in a digital broadcast transmission system in which enhanced data is formatted in a group unit and the formatted group data is transmitted to form a burst. Extracting group information and burst information located in a reserved area of the signal may cut off power of a part of the receiver.

According to an aspect of the present invention, there is provided a digital broadcast reception system including: a receiver configured to receive a plurality of consecutive enhanced data packets when they are grouped and transmitted in burst units; And a burst control unit supplying power to the receiving unit only in the burst period with reference to the input burst information.

The receiver comprises a demodulation and equalization unit for performing demodulation and channel equalization by applying known data to the received signal when the digital broadcast signal is received; And a known data detection unit for detecting known data inserted by the transmitting side from the before and / or after demodulation signal and outputting the known data to the demodulation and equalization unit with reference to the known data information inputted therein.

In accordance with another aspect of the present invention, there is provided a digital broadcast receiving method comprising: receiving a plurality of consecutive enhanced data packets when they are grouped and transmitted in burst units; And controlling the power on / off to receive the enhanced data only in the burst section.

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

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

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

The present invention is to improve the reception performance of a receiver by inserting and transmitting known data previously known from a transmitting / receiving side to a predetermined position in an enhanced data packet and using the same at the receiver.

In particular, the transmitting side of the present invention groups at least one enhanced data packet and transmits at least one group in burst units.

In the reception side of the present invention, when only the enhanced data is received, the power is turned on only in the burst section and turned off in the other sections, thereby reducing power consumption of the receiver.

At least one enhanced data packet group may be multiplexed in at least one burst, or at least one enhanced data packet group and main data packets may be multiplexed.

The multiplexing apparatus in the digital broadcast transmission system according to an embodiment of the present invention for this purpose is an E-VSB preprocessor 301, an E-VSB packet formatter 302, a packet multiplexer 303, and a scheduler as shown in FIG. Scheduler 310).

In the present invention configured as described above, the main data is output to the packet multiplexer 303 in transport packet units, and the enhanced data is output to the E-VSB preprocessor 301. The E-VSB preprocessor 301 performs preprocessing such as additional error correction encoding, interleaving, null data insertion, and the like on the enhanced data and outputs the same to the E-VSB packet formatter 302.

The E-VSB packet formatter 302 forms a group by multiplexing the preprocessed enhanced data and predefined known data under the control of the scheduler 310. Subsequently, the data in the group is divided into enhanced data packets of 184 bytes, and a 4-byte MPEG header is added before the packet to output an enhanced data packet of 188 bytes (ie, an MPEG compatible packet). That is, one enhanced data packet group includes a plurality of consecutive enhanced data packets.

The output of the E-VSB packet formatter 302 is input to the packet multiplexer 303. The packet multiplexer 303 time-division multiplexes the main data packet and the enhanced data packet group by a transport stream (TS) packet unit under the control of the scheduler 310.

That is, the scheduler 310 generates and outputs a control signal to multiplex the enhanced data and the known data in the packet formatter 302, and also outputs the main data packet and the enhanced data packet in the packet multiplexer 303. Outputs a control signal to multiplex the group. The packet multiplexer 303 receives a control signal and multiplexes a main data packet and an enhanced data packet group in units of TS packets.

At this time, the transmission parameters for the multiplexing of the packet formatter 302 and the packet multiplexer 303 may be multiplexed and output together when the enhanced data and the known data are multiplexed under the control of the scheduler 310. When the main data packet and the enhanced data packet group are multiplexed at 303, they may be multiplexed together and output. Alternatively, the transmission parameter may be inserted into an unused area of an ATSC VSB field sync segment and transmitted.

That is, the transmission parameter may be inserted and transmitted at a predetermined position of the group, and / or may be inserted and transmitted in an unused area of the field sync segment.

The transmission parameter includes information on the length of the current burst, information indicating the time of the next burst, location and length of the groups in the burst, time from the current group to the next group in the burst, and information on known data. can do. The transmission parameter may use certain fixed values and may use values that are variable in real time.

4 illustrates an embodiment of a burst multiplexing method of the packet multiplexer. In FIG. 4, a group is composed of a plurality of consecutive enhanced data packets, and a plurality of enhanced data packet groups are gathered to form one burst.

In this case, a plurality of consecutive enhanced data packets are multiplexed and transmitted in a group unit, which is possible when the known data inserted in the E-VSB packet formatter 302 is trellis-coded and finally transmitted in the digital broadcasting transmission system. This is to maximize the reception performance of the receiving system by outputting continuously.

However, when the length of the enhanced data packet group (that is, the number of enhanced data packets in the group) is too large, a problem may arise in terms of compatibility with the existing ATSC digital broadcast receiver receiving the main data packet. In the conventional ATSC digital broadcast receiver, the enhanced data packet is discarded after seeing the PID (Packet Identifier) of the enhanced data packet, because if the main data packet is not received for a long time, there may be a problem in controlling the buffer.

Therefore, according to the present invention, the enhanced data packets are multiplexed into group units having a predetermined length or less, and multiplexed with the main data packets within one burst.

In addition, in FIG. 4, NBT (Next Burst Time) means a time until the start time of the next burst in each enhanced data packet group in the current burst.

In the present invention, the next burst time (NBT) is inserted and transmitted for each group in the current burst or in a specific group, and the next burst time is inserted into a predetermined area of the group. This next burst time (NBT) is determined by the scheduler 310 and provided to the E-VSB packet formatter 302, and the E-VSB packet formatter 302 inserts it into a specific area of the enhanced data packet group and outputs it. Do it.

As can be seen from FIG. 4, it can be seen that the next burst time NBT continues to decrease from group G1 to G2 and G3 of the current burst 1 (NBTG1> NBTG2> NBTG3). In this case, the reason why the next burst time is repeatedly inserted into the group is to allow the receiver to find out the next burst time through the reception of another group even when an error occurs in the reception of a specific group.

FIG. 5 is a block diagram illustrating an entire configuration of a digital broadcast transmission system according to an embodiment of the present invention to which the multiplexing apparatus of FIG. 3 is applied, including an E-VSB preprocessor 501, an E-VSB packet formatter 502, and a packet multiplexer. 503, data randomizer 504, scheduler 505, E-VSB post-processor 510, RS encoder 521, data interleaver 522, trellis encoder 523, compatibility processor 524 ), A frame multiplexer 525, and a transmitter 530.

Since detailed operations of the E-VSB preprocessor 501, the E-VSB packet formatter 502, the packet multiplexer 503, and the scheduler 505 have been described above, they will be omitted. In addition, the remaining parts refer to patents (application number 2005-90175, application date 2005.09.27) previously filed by the present applicant and detailed description thereof will be omitted.

FIG. 6 is a block diagram illustrating an entire configuration of a digital broadcast transmission system according to another embodiment of the present invention to which the multiplexing apparatus of FIG. 3 is applied, including an E-VSB preprocessor 601, an E-VSB packet formatter 602, and a packet multiplexer. 603, data randomizer 604, scheduler 605, RS encoder and parity position holder inserter 606, data interleaver 607, byte-to-symbol converter 608, E-VSB symbol processing unit 609 ), A known data generator 610, a symbol-byte converter 611, an unstructured RS encoder 612, a trellis encoder 613, a frame multiplexer 614, and a transmitter 620. .

The E-VSB packet formatter 602 of FIG. 6 determines the known data location holder into which the known data in the packet is to be inserted, inserts null data into the determined known data location holder, and then inserts the null data into the determined known data location holder. A group is formed by multiplexing with the output data of the preprocessor 601. Subsequently, the data in the group is divided into enhanced data packets of 184 bytes, and a 4-byte MPEG header is added before the packet to output an enhanced data packet of 188 bytes (ie, an MPEG compatible packet). That is, one enhanced data packet group includes a plurality of consecutive enhanced data packets.

Since the operations of the packet multiplexer 603 and the scheduler 605 of FIG. 6 may be referred to the operations of the packet multiplexer and the scheduler of FIG. 3, detailed description thereof will be omitted. In addition, the remaining parts refer to patents (Application No. 2005-93639, filing date 2005.10.05) previously filed by the present applicant and detailed description thereof will be omitted.

Meanwhile, the reason why the enhanced data packet is transmitted in burst units is to enable the receiver to receive data by turning on the receiver only in the burst period in the receiver receiving only the enhanced data. It is particularly useful for portable receivers that need to be small.

7 is a block diagram illustrating an embodiment of a digital broadcast receiving system according to the present invention.

7 is largely comprised of a receiver 700 and a burst controller 800 for controlling the power supply of the receiver 700.

The receiver 700 includes a tuner 701, a demodulator 702, an equalizer 703, a known data detector 704, a Viterbi decoder 705, a data deinterleaver 706, an RS decoder and an RS parity agent. Reject 707, derandomizer 708. The receiver 700 includes a main data packet remover 709, an E-VSB packet deformatter 710, a parameter detector 711, and an enhanced data processor 712.

That is, the tuner 701 tunes down-converts the frequency of a specific channel and outputs the demodulator 702 and the known data detector 704.

The demodulator 702 performs carrier recovery and timing recovery on the tuned channel frequency to form a baseband signal and outputs the same to the equalizer 703 and the known data detector 704. If the transmission data related to the known data, the enhanced data packet group, and the burst are inserted into the field sync segment and transmitted, this information is output to the parameter detector 711.

The equalizer 703 compensates for the distortion on the channel included in the demodulated signal and outputs it to a Viterbi decoder 705.

At this time, the known data detector 704 detects a known data symbol string inserted at the transmitting side from the output data of the tuner 701 and / or the demodulator 702 to the demodulator 702 and the equalizer 703. Output

The demodulator 702 can improve demodulation performance by using the known data during timing recovery or carrier recovery, and can equalize performance using the known data in the equalizer 703 as well.

The Viterbi decoder 705 performs Viterbi decoding on the main symbol and the enhanced data symbol output from the equalizer 703, converts the result into bytes, and outputs the result to the deinterleaver 706. The deinterleaver 706 performs an inverse process of the data interleaver on the transmitter side and outputs the deinterleaver 706 to an RS decoder and an RS parity remover 707.

The RS decoder and the RS parity remover 307 perform RS decoding when the received packet is a main data packet. When the received packet is an enhanced data packet, parity bytes are removed without performing RS decoding. The operation varies depending on the structure of the digital broadcasting transmission system.

For example, if the enhanced data packet transmitted in the digital broadcast transmission system as shown in FIG. 5 is removed, the last 20 bytes of the corresponding data packet is removed, and if the enhanced data packet transmitted in the digital broadcast transmission system as shown in FIG. The 20-byte unstructured RS parity position holder located in the middle of the packet is removed and output to the derandomizer 708.

The derandomizer 708 performs a reverse process of the randomizer on the outputs of the RS decoder and the RS parity remover 707 and inserts MPEG sync bytes in front of every packet to output 188 byte packets.

The output of the derandomizer 708 is output to the main MPEG decoder (not shown) and to the main data packet remover 709. The main MPEG decoder decodes only packets corresponding to the main MPEG. If the packet ID is a null packet PID (ie, an enhanced data packet), no decoding is performed.

Meanwhile, the main data packet remover 709 removes the main data packet in units of 188 bytes from the output of the derandomizer 708 and outputs only the enhanced data packet to the E-VSB packet deformatter 710. .

The E-VSB packet deformatter 710 removes the MPEG header from the enhanced data packet output from the main packet remover 709 to obtain a packet of 184 bytes. The 184 byte packets are collected to form a group having a predetermined size, and the known data or known data position holder inserted in the demodulation and equalization at the transmitting side is removed at the predetermined position and then output to the enhanced data processor 712. .

In addition, the E-VSB packet deformatter 710 outputs the information to the parameter detector 711 if the known data, the enhanced data packet group, and the transmission parameter related to the burst are inserted and transmitted at a predetermined position in each group. In this case, the known data or the data from which the known data position holder is removed is composed of enhanced data on which E-VSB preprocessing is performed, and transmission parameters for groups and bursts.

The parameter detector 711 detects the information on the known data from the transmission parameters multiplexed in the field sync segment and / or the group and outputs the information to the known data detector 704, detects the information on the burst, and the burst controller 800 )

In this case, since the known data is inserted into the group differently for each packet, the information about the group obtained after the E-VSB packet deformatter is extracted, and the known data detector 704 receives the information about the known data and can be used to detect the known data. have. In addition, when the known data is inserted in a predetermined position in a predetermined manner, the known data may be detected in advance and used for demodulation and equalization before extracting information about the group.

The enhanced data processor 712 performs the reverse process of the EVSB preprocessor of the transmitter on the output of the EVSB packet deformatter 710 to finally output the enhanced data.

The burst control unit 800 supplies power so that the receiver 700 operates in the current burst section according to the input burst information, and receives the receiver 700 until the next burst section without the enhanced data to be received after the current burst section ends. Turn off the power). This reduces the power consumption of the receiver. In particular, this is to reduce power consumption in a section in which there is no desired enhanced data when the main data and the enhanced data are multiplexed and only want to receive specific enhanced data.

As such, when the burst control unit 800 receives only the enhanced data, the burst control unit 800 supplies power to the receiving unit 700 in the burst period, and cuts off the power supplied to the receiving unit 700 in the other periods of the receiver. The power consumption can be reduced. That is, data may be received only in a burst in which a group consisting of enhanced data exists, and power consumption of a part of the receiver may be cut off in a section other than the burst section, thereby reducing power consumption.

As described above, the digital broadcasting system, the method, and the data structure according to the present invention have the advantage of being resistant to errors and compatible with existing VSB receivers when transmitting additional data through a channel. In addition, there is an advantage that the additional data can be received without error even in a ghost and noisy channel than the conventional VSB system.

In addition, the present invention can improve the reception performance of a receiving system with a large channel change by inserting and transmitting known data in a specific position of the data area. In particular, the present invention is more effective when applied to portable and mobile receivers that require severe channel changes and robustness against noise.

In addition, the present invention can improve the reception performance of the receiving system by grouping and transmitting a plurality of consecutive enhanced data packets. In particular, by transmitting at least one group in burst units, it is possible to improve the reception performance of a receiver receiving only enhanced data, which is more effective when applied to portable and mobile receivers that require severe channel changes and robustness against noise. .

As described above, those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

Claims (14)

delete delete delete delete delete delete delete delete A tuner for receiving a broadcast signal including enhanced data, known data, main data, and transmission parameters; A demodulator for demodulating the received broadcast signal; A known data detector for detecting known data from the demodulated broadcast signal; An equalizer for compensating for channel distortion of the demodulated broadcast signal using the detected known data; A decoder that decodes enhanced data included in the broadcast signal whose channel distortion is compensated for; And A controller for controlling a power supply of the tuner and a demodulator on the basis of a transmission parameter included in the broadcast signal, The enhanced data included in the broadcast signal received by the tuner performs a first RS (Reed-Solomon) encoding on the enhanced data in a digital broadcasting transmission system and weaves the enhanced data on the first RS encoded data ( convolutional) encoding, deinterleaving the convolutional encoded data, performing a second RS encoding on the deinterleaved enhanced data, and performing a second RS encoding on the second RS encoded enhanced data. Generated by performing interleaving and trellis coding on the interleaved enhanced data, The transmission parameter includes information for power control of the tuner and the demodulator, and is inserted and received at a predetermined position in a data group including the enhanced data and known data. The method of claim 9, And a de-randomizer for performing de-randomization on the decoded enhanced data. The method of claim 9, The received broadcast signal further comprises a segment synchronization signal and a field synchronization signal. Receiving at the tuner a broadcast signal comprising enhanced data, known data, main data, and transmission parameters; Demodulating the received broadcast signal in a demodulator; Detecting known data from the demodulated broadcast signal; Compensating for channel distortion of the demodulated broadcast signal using the detected known data; Decoding enhanced data included in the broadcast signal whose channel distortion is compensated for; And Controlling power of the tuner and the demodulator on the basis of transmission parameters included in the broadcast signal, The enhanced data included in the broadcast signal received by the tuner performs a first RS (Reed-Solomon) encoding on the enhanced data in a digital broadcasting transmission system and weaves the enhanced data on the first RS encoded data ( convolutional) encoding, deinterleaving the convolutional encoded data, performing a second RS encoding on the deinterleaved enhanced data, and performing a second RS encoding on the second RS encoded enhanced data. Generated by performing interleaving and trellis coding on the interleaved enhanced data, The transmission parameter includes information for power control of the tuner and the demodulator, and is inserted and received at a predetermined position in a data group including the enhanced data and known data. Treatment method. 13. The method of claim 12, And performing de-randomizing on the decoded enhanced data. 13. The method of claim 12, The received broadcast signal further comprises a segment synchronization signal and a field synchronization signal.

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