KR101314614B1 - Digital broadcasting system and method of processing data - Google Patents

Abstract

The present invention relates to an error-tolerant digital transmission system and a data processing method when transmitting mobile service data. To this end, the present invention performs additional coding on mobile service data and transmits the same. By doing so, robustness to the mobile service data can be imparted, and it is possible to strongly cope with rapid channel change.

Moving, data rate, transmitter

Description

Digital broadcasting system and method of processing data

1 is a schematic structural block diagram of a digital transmission system according to an embodiment of the present invention;

2 is a block diagram showing an embodiment of the service multiplexer of FIG.

3 is a block diagram illustrating an embodiment of the transmitter of FIG.

4 is a block diagram illustrating an embodiment of the preprocessor of FIG. 3.

5 illustrates a structure of a burst and a data group according to an embodiment of the present invention.

6 is a diagram illustrating a data rate adjustment example according to an embodiment of the present invention as a data structure.

7 is a flowchart illustrating an example of data rate adjustment according to an embodiment of the present invention.

8 is a diagram illustrating a data structure of an example of adjusting a data rate according to another embodiment of the present invention.

9 is a flowchart illustrating an example of adjusting a data rate according to another embodiment of the present invention.

10 is a flowchart illustrating an example of adjusting a data rate according to another embodiment of the present invention.

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

Description of the Related Art [0002]

100: service multiplexer 110: controller

120: PSI / PSIP Generator 130: PSI / PSIP Generator

140: null packet generator 150: mobile service multiplexer

160: transport multiplexer 161: main service multiplexer

162: transport packet multiplexer

200 transmitter 211 demultiplexer

212: PSI / PSIP decoder 213: main data buffer

214: Packet Jitter Reducer 215: Mobile Data Buffer

216: preprocessor 217: buffer controller

218: signaling information provider 219: packet multiplexer

220: post-processor 230: synchronous multiplexer

240: transmitter

The present invention relates to a digital broadcasting system, and more particularly, to an apparatus and method for transmitting and receiving digital broadcasting.

VSB (Vestigial Sideband) transmission system adopted as a digital broadcasting standard in North America and Korea in digital broadcasting is a single carrier system, so reception performance of a receiving system may be deteriorated in a poor channel environment. Particularly, in the case of a portable or mobile broadcasting receiver, robustness against channel change and noise is further required, so that when the mobile service data is transmitted by the VSB transmission method, the reception performance is further deteriorated.

Accordingly, the present invention provides a digital broadcasting system and a data processing method that are robust against channel variation and noise.

The present invention provides a digital broadcasting system and a data processing method for improving reception performance by performing additional coding on mobile service data and transmitting the same to a receiving system.

The present invention provides a digital broadcasting system and a data processing method for adjusting and matching a data rate in a transmitter when a difference occurs between a data rate of a service multiplexer and a data rate of a transmitter.

In order to achieve the above object, a data processing method of a transmitter in a transmission system according to an embodiment of the present invention comprises the steps of comparing the transmission data rate of the transmitter and the output data rate of the service multiplexer; Adjusting a size of a burst for transmitting mobile service data and performing encoding when a difference occurs between the two data rates of the step; And multiplexing the main service data and the encoded mobile service data into a burst structure with reference to the burst size of the step.

 A data processing method of a transmitter in a transmission system according to another embodiment of the present invention includes the steps of comparing the output data rate of the service multiplexer and the transmission data rate of the transmitter; Adjusting a period of a burst for transmitting mobile service data and performing encoding when a difference between two data rates of the step occurs; And multiplexing the main service data and the encoded mobile service data into a burst structure with reference to the burst period of the step.

 A data processing method of a transmitter in a transmission system according to another embodiment of the present invention comprises the steps of comparing the output data rate of the service multiplexer and the transmission data rate of the transmitter; Adjusting a data rate by inserting or removing transmission null data in the mobile service data when a difference occurs between the two data rates of the step; Performing encoding on the mobile service data into which the transmission null data is inserted or removed in the step; And multiplexing main service data and the encoded mobile service data into a burst structure.

The service multiplexer of the transmission system according to an embodiment of the present invention includes a mobile service multiplexer, a null packet generator, and a transport packet multiplexer. The mobile service multiplexer multiplexes at least one kind of mobile service data, a PSI / PSIP table for the mobile service, and filled channel data at a preset first data rate. The null packet generator generates filled null data and outputs the filled null data to the mobile data multiplexer to match the output data rate of the mobile service multiplexer to a first data rate. The transport packet multiplexer multiplexes at least one kind of main service data and a PSI / PSIP table for the main service at a preset second data rate, and then multiplexes data output from the mobile service multiplexer at a preset third data rate. Output to the remote transmitter.

A transmitter of a transmission system according to an embodiment of the present invention includes a demultiplexer, a buffer, a preprocessor, a buffer controller, and a packet multiplexer. The demultiplexer receives data transmitted at a predetermined data rate from the service multiplexer and distinguishes mobile service data, main service data, and filled channel data. The buffer temporarily stores and outputs mobile service data classified by the demultiplexer. The preprocessor performs encoding on the output data of the buffer. The buffer controller monitors the input / output data rate of the buffer and adjusts the data rate by adjusting a burst related transmission parameter for transmitting mobile service data when a difference occurs between the two data rates. The packet multiplexer multiplexes the main service data packet including the mobile service data packet and the main service data output from the preprocessor with a burst structure by referring to the transmission parameter.

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.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. 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.

In addition, the terminology used in the present invention is a general term that is widely used as possible while considering functions in the present invention, but may vary according to the intention or custom of a person skilled in the art or the emergence of a new technology. In addition, in certain cases, there is a term arbitrarily selected by the applicant, and in this case, the meaning will be described in detail in the corresponding description of the invention. Therefore, it is to be understood that the term used in the present invention should be defined based on the meaning of the term rather than the name of the term, and on the contents of the present invention throughout.

Among the terms used in the present invention, main service data may include audio / video (A / V) data as data that can be received by a fixed receiving system. That is, the main service data may include HD (High Definition) or SD (Standard Definition) A / V data, and various data for data broadcasting may be included. The known data is previously known data by the promise of the transmitting / receiving side.

In addition, the mobile service data in the present invention includes at least one of the mobile (Mobile) data, the service data (Pedestrian), handheld (Handheld) service data, in the present invention for convenience of description This is called service data. At this time, the mobile service data may include not only M / P / H (Mobile / Pedestrian / Handheld) service data, but also service data indicating movement or carrying, Service data.

The mobile service data defined above may be data having information such as a program executable file, stock information, etc., or A / V data. In particular, the mobile service data may be service data for a portable or mobile terminal (or broadcast receiver), and may be A / V data having a smaller resolution and smaller data rate than the main service data. For example, if the A / V codec used for the existing main service is an MPEG-2 codec, the A / V codec for mobile service may be MPEG-4 AVC (Advanced Video Coding), and SVC (Scalable Video Coding). Also, any kind of data can be transmitted as the mobile service data. For example, TPEG (Transport Protocol Expert Group) data for broadcasting traffic information in real time may be serviced.

In addition, data services using the mobile service data include weather services, transportation services, securities services, viewer participation quiz program, real-time polls, interactive educational broadcasting, game services, drama plot, characters, background music, shooting location, etc. Informational services, historical information about sports, past athletes' profiles and grades, and information on programs, by media, by hour, or by topic, to enable product information and ordering. Etc., but the present invention is not limited thereto.

The transmission system according to the present invention is capable of multiplexing the main service data and the mobile service data on the same physical channel without any influence on receiving the main service data in the existing receiving system.

In addition, the transmission system of the present invention performs additional encoding on the mobile service data, and inserts and transmits the data that is known in advance, that is, known data.

With the transmission system according to the present invention, mobile service data can be received and received in the receiving system, and stable reception of mobile service data is possible even with various distortions and noises occurring in the channel.

The present invention also enables the transmitter to adjust the data rate when a difference occurs between the data rate of the service multiplexer in the transmission system and the data rate of the transmitter.

In particular, the present invention allows the transmitter to adjust the difference in data rate when a difference occurs between the mobile service data rate output from the service multiplexer and the data rate transmitted by the transmitter.

FIG. 1 is a schematic diagram illustrating an embodiment of a transmission system for applying the present invention. The transmission multiplexer 100 may include a service multiplexer 100 and a transmitter 200.

Here, the service multiplexer 100 is located in a studio of each broadcasting station, and the transmitter 200 is located in a site away from the studio. At this time, the transmitter 200 may be located in a plurality of different areas. The plurality of transmitters may share the same frequency, in which case the plurality of transmitters all transmit the same signal. Then, in the receiving system, the channel equalizer compensates the signal distortion due to the reflected wave to restore the original signal. Various methods may be used for the data communication between the service multiplexer and each remote transmission station, and an interface standard such as SMPTE-310M (Synchronous Serial Interface for transport of MPEG-2 data) may be used . In the SMPTE-310M interface standard, the output data rate of the service multiplexer is fixed at a constant data rate. For example, it is set at 19.39 Mbps for 8VSB and 38.78 Mbps for 16VSB. Also, in the conventional 8VSB transmission system, a transport stream (TS) packet having a data rate of about 19.39 Mbps can be transmitted to one physical channel. In the transmitter according to the present invention having backward compatibility with the existing transmission system, an additional error correction encoding is performed on the mobile service data and then multiplexed and transmitted in the form of a main service data and a TS packet. The data rate of the TS packet is about 19.39 Mbps.

In this case, the service multiplexer 100 receives at least one type of mobile service data and a Program Specific Information (PSI) / Program and System Information Protocol (PSIP) table for each mobile service, respectively, and is a transport stream (TS) packet. Encapsulation. In addition, the service multiplexer 100 receives at least one kind of main service data and a PSI / PSIP table for each main service and encapsulates them into TS packets. And multiplexes the TS packets according to a preset multiplexing rule and outputs the multiplexed TS packets to the transmitter 200.

FIG. 2 is a detailed block diagram illustrating an embodiment of the service multiplexer. The controller 110 controls overall operation of the service multiplexer, a PSI / PSIP generator 120 for a main service, and a mobile service. The PSI / PSIP generator 130 may include a null packet generator 140, a mobile service multiplexer 150, and a transport multiplexer 160.

The transport multiplexer 160 may include a main service multiplexer 161 and a transport stream (TS) packet multiplexer 162.

Referring to FIG. 2, at least one type of compressed coded main service data and a PSI / PSIP table generated by the PSI / PSIP generator 120 for the main service are included in the main service multiplexer 161 of the transport multiplexer 160. ) Is entered. The main service multiplexer 161 encapsulates the input main service data and the PSI / PSIP table in the form of MPEG-2 TS packets, respectively, and multiplexes these TS packets to the TS packet multiplexer 162. Output The data packet output from the main service multiplexer 161 will be referred to as a main service data packet for convenience of explanation.

In addition, at least one type of compressed-coded mobile service data and a PSI / PSIP table generated by the PSI / PSIP generator 130 for the mobile service are input to the mobile service multiplexer 150. In this case, the PSI / PSIP table for the mobile service may include at least one transmission parameter corresponding to each mobile service. In this case, the PSI / PSIP generator 130 generates a transmission parameter under the control of the mobile service multiplexer 150 and then includes the PSI / PSIP generator 130 in a corresponding table in the PSI / PSIP table that is previously promised with the transmitter 200. Output to 150 is possible.

The mobile service multiplexer 150 encapsulates the input mobile service data and the PSI / PSIP table in the form of MPEG-2 TS packets, respectively, and multiplexes these TS packets to the TS packet multiplexer 162. Output The data packet output from the mobile service multiplexer 150 will be referred to as a mobile service data packet for convenience of description.

At this time, the transmitter 200 needs identification information to separate and process the main service data packet and the mobile service data packet. The identification information may be a predetermined value in accordance with the promise of the transmitting / receiving side, may be composed of separate data, or may be used by modifying a value of a predetermined position in the data packet. Since the identification information can be any value that can distinguish each data packet, the present invention will not be limited to the above-described embodiment.

In an embodiment of the present invention, different PIDs (Packet Identifiers) may be allocated to the main service data packet and the mobile service data packet, respectively.

In another embodiment, by modifying the sync byte in the header of the mobile service data packet, it may be distinguished using the sync byte value of the corresponding service data packet. For example, the synchronous byte of the main service data packet is output without modification as it is defined in ISO / IEC13818-1 (for example, 0x47), and the synchronous byte of the mobile service data packet is transformed and output, It is possible to distinguish between the data packet and the mobile service data packet. Conversely, the main service data packet and the mobile service data packet can be distinguished by modifying the synchronization byte of the main service data packet and outputting the synchronization byte of the mobile service data packet without modification.

There are various methods for modifying the sync byte. For example, the synchronization byte may be inverted bit by bit, or only some bits may be inverted.

As such, any value that can distinguish the main service data packet and the mobile service data packet may be any, and thus the present invention will not be limited to the above-described embodiments.

Meanwhile, the transport multiplexer 160 can use the transport multiplexer used in the existing digital broadcasting system as it is. That is, to multiplex the mobile service data with the main service data, the data rate of the main service is limited to a data rate of (19.39-K) Mbps, and K Mbps corresponding to the remaining data rate is allocated to the mobile service. By doing so, the already used transport multiplexer can be used without modification.

The transport multiplexer 160 multiplexes the main service data packet output from the main service multiplexer 161 and the mobile service data packet output from the mobile service multiplexer 150 and transmits the multiplexed data to the transmitter 200.

However, it may happen that the output data rate of the mobile service multiplexer 150 is less than K Mbps. In this case, the mobile service multiplexer 150 multiplexes and outputs null data packets generated in the null packet generator 140 such that the output data rate becomes K Mbps. That is, the null packet generator 140 generates a null data packet to output the output data rate of the mobile service multiplexer 150 to the mobile service multiplexer 150 in order to keep the output data rate constant. In the present invention, a null data packet generated by the null packet generator 140 will be referred to as a null data packet for filler for convenience of description.

For example, if K Mbps of 19.39 Mbps is assigned to mobile service data in the service multiplexer 100 and the remaining (19.39-K) Mbps is allocated to main service data, the service multiplexer 100 ), The data rate of the mobile service data multiplexed is smaller than K Mbps. This is because, in the case of the mobile service data, the amount of data is increased by performing additional encoding in a pre-processor of the transmitter. As a result, a data rate of mobile service data that can be transmitted by the service multiplexer 100 is reduced.

For example, the preprocessor of the transmitter performs coding of at least a half coding rate for mobile service data, so that the amount of output data of the preprocessor becomes twice as much as the amount of input data. Therefore, the sum of the data rate of the main service data multiplexed in the service multiplexer 100 and the data rate of the mobile service data is always less than or equal to 19.39 Mbps.

Therefore, in order to adjust the final output data rate output from the service multiplexer 100 to a constant data rate (for example, 19.39 Mbps), the null packet generator 140 generates a filled null data packet by a data rate that is short. To the mobile service multiplexer 150.

Then, the mobile service multiplexer 150 encapsulates the input mobile service data and the PSI / PSIP table in the form of MPEG-2 TS packets, respectively, and multiplexes the TS packets and the filled null data packet to TS. Output to the packet multiplexer 162.

The transport multiplexer 160 multiplexes the main service data packet output from the main service multiplexer 161 and the mobile service data packet output from the mobile service multiplexer 150 to the transmitter 200 at a 19.39 Mbps data rate. send.

According to an embodiment of the present invention, the mobile terminal multiplexer 150 receives a filled null data packet. This is only one embodiment. In another embodiment, the TS packet multiplexer 162 receives the filled null data packet and adjusts the final data rate to a constant data rate. The output path and the multiplexing rule of the filled null data packet are controlled by the controller 110. The controller 110 controls the multiplexing and null packet generators 140 in the mobile service multiplexer 150, the main service multiplexer 161 of the transport multiplexer 160, and the TS packet multiplexer 162. Controls the generation of filled null data packets.

At this time, the transmitter 200 discards the filled null data packet transmitted from the service multiplexer 100 without transmitting it to the receiving system.

In order to discard the filled null data packet without transmitting the transmitter 200, identification information capable of distinguishing the filled null data packet is required. The identification information for distinguishing the filled null data packet may use a value predetermined by an appointment of the transmitting / receiving side or may be configured as separate data. For example, the sync byte value in the header of the filled null data packet may be modified to be used as identification information, or a transport_error_indicator flag may be used as identification information. The identification information may be any one capable of distinguishing a filled null data packet, and thus the present invention will not be limited to the above-described embodiment.

According to an embodiment of the present invention, the transport_error_indicator flag of the header in the filled null data packet is used as identification information for identifying the filled null data packet. In this case, the transport_error_indicator flag of the filled null data packet is set to 1, and the transport_error_indicator flag of all data packets other than the filled null data packet is reset to 0 to distinguish the filled null data packet. That is, when the null packet generator 140 generates the filled null data packet, if the transport_error_indicator flag is set to '1' in the field of the header of the filled null data packet, the transmitter 200 may separate the discard packet packet.

3 is a block diagram illustrating a transmitter 200 according to an embodiment of the present invention, which includes a demultiplexer 211, a PSI / PSIP decoder 212, a main data buffer 213, and a packet jitter reducer. (Packet jitter mitigator) 214, mobile data buffer 215, pre-processor (216), buffer controller 217, signaling information provider 218, packet multiplexer 219, post processor And a post-processor (220), a sync multiplexer (230), and a transmission unit (240).

The data packet transmitted from the service multiplexer 100 is input to the demultiplexer 211 and the PSI / PSIP decoder 212 of the transmitter 200.

The demultiplexer 211 distinguishes whether a data packet input by the control of the PSI / PSIP decoder 212 is a main service data packet, a mobile service data packet, or a filled null data packet.

The filled null data packet separated by the demultiplexer 211 is discarded without being transmitted, and the main service data packet is provided to the packet jitter reducer 214 via the main data buffer 213, and the mobile service data packet is mobile. The data buffer 215 is provided to the preprocessor 216.

In this case, there may be various methods for distinguishing whether the data packet input to the demultiplexer 211 is a main service data packet, a mobile service data packet, or a filled null data packet.

In an embodiment, the mobile service data packet and the main service data packet may be distinguished according to the PID value of the input data packet, and the filled null data packet may be distinguished according to the transport_error_indicator flag value.

The PSI / PSIP decoder 212 receives a PSI / PSIP table for the main service and a PSI / PSIP table for the mobile service among data transmitted from the service multiplexer 100, and configures the program of the main service and the program of the mobile service. Identify the configuration.

In addition, the PSI / PSIP decoder 212 refers to the PID of the currently input data packet and the transport_error_indicator flag, and whether the data packet input to the demultiplexer 211 is a main service data packet, a mobile service data packet, or a filled null. After generating a control signal that can distinguish whether the data packet or not and outputs to the demultiplexer (211). Then, the demultiplexer 211 classifies the data packets input according to the control signal, and then discards the separated data packets or outputs them to the corresponding block.

In this case, the PSI / PSIP table for the mobile service may include at least one transmission parameter corresponding to each mobile service. In this case, the PSI / PSIP decoder 212 parses it and outputs it to the signaling information provider 218. The signaling information providing unit 218 may transmit the transmission parameters so that related blocks (eg, a preprocessor, a packet multiplexer, etc.) of the transmitter 200 may utilize the transmission parameters under the control of the buffer controller 217. Provides signaling information including the related blocks.

For example, the transmission parameter may include data group information, region information in the data group, RS frame information, super frame information, burst information, turbo code information, RS code information, and the like. In addition, the burst information may include burst size information, burst period information, and the like. The burst period means a period in which bursts transmitting the same type of mobile service are repeated, and the burst size means the number of data groups included in one burst. The data group includes a plurality of mobile service data packets, and these data groups are gathered to form a burst. The burst section means the period from the start of the current burst to the start of the next burst, and is divided into a section including a data group (that is, a burst on section) and a section without a data group (burst off section). . One burst period consists of a plurality of fields, and one field includes one data group.

The information included in the transmission parameter is merely an example for facilitating understanding of the present invention. Addition and deletion of information included in the transmission parameter can be easily changed by those skilled in the art. Therefore, the present invention is not limited to the above embodiment I will not.

In this case, the transmission parameter provided by the signaling information provider 218 may vary according to the buffer controller 217. For example, the burst size, burst period, and the like can be varied. The signaling information output from the signaling information provider 218 includes a transmission parameter.

The preprocessor 216 performs additional encoding on the mobile service data and outputs it to the packet multiplexer 219 in order to respond quickly and strongly to noise and channel changes.

4 is a block diagram showing an embodiment of the preprocessor 216 according to the present invention, which includes a data randomizer 401, an RS frame encoder 402, a block processor 403, a group formatter 404, and data. A deinterleaver 405, and a packet formatter 406.

The preprocessor 216 according to the present invention performs additional encoding on the mobile service data output from the mobile data buffer 215 with reference to the transmission parameter provided by the signaling information provider 218. Explain as.

That is, the data renderer 401 randomizes the input mobile service data and outputs the data to the RS frame encoder 402. At this time, the data renderer 221 of the post-processor 220 may skip the process of rendering the mobile service data by performing the rendering of the mobile service data in the data renderer 401.

The RS frame encoder 402 forms a RS frame by combining a plurality of pieces of mobile service data, which are input after being rendered, and performs at least one of an error correction encoding process and an error detection encoding process on an RS frame basis. In addition, a plurality of RS frames may be gathered to form a super frame, and interleaving or permutation may be performed on a super frame basis. This provides robustness to mobile service data, and can cope with extremely poor and rapidly changing radio environments.

That is, when the RS frame encoder 402 performs interleaving by mixing each column of the super frame with a predetermined rule, the positions of the rows before and after interleaving in the super frame are changed. When the interleaving is performed in the unit of the super frame, even if an error that cannot be corrected is included in one RS frame to be decoded because the interval in which a large amount of error occurs is very long, the error is distributed in the entire super frame, so that the decoding is compared with a single RS frame. Improve your skills.

The RS frame encoder 402 applies RS coding for error correction coding and CRC (Cyclic Redundancy Check) coding for error detection coding. When the RS coding is performed, parity data to be used for error correction is generated, and CRC coding is performed to generate CRC data to be used for error detection.

In one embodiment, the RS encoding uses a forward error correction (FEC) structure. The FEC refers to a technique for correcting an error occurring in a transmission process. The CRC data generated by the CRC encoding can be used to indicate whether the mobile service data is transmitted through the channel and is damaged by an error. The present invention may use other error detection coding methods other than CRC coding, or may improve the overall error correction capability on the receiving side by using an error correction coding method.

In this case, the RS frame encoder 402 refers to a preset transmission parameter and / or a transmission parameter provided by the signaling information provider 218 to configure an RS frame configuration, RS encoding, CRC encoding, super frame configuration, and super. Frame interleaving may be performed.

The mobile service data encoded by the RS frame encoder 402 is input to the block processor 403 as described above.

The block processor 403 encodes the input mobile service data again with G / H (where G < H) and outputs the encoded data to the group formatter 404.

That is, the block processor 403 divides the mobile service data input in byte units into bits, encodes the separated G bits into H bits, and converts the converted G bits into bytes. For example, if one bit of input data is encoded into two bits and outputted, G = 1 and H = 2. If one bit of input data is encoded into four bits and outputted, G = 1 and H = 4. In the present invention, for convenience of description, the former is referred to as encoding at 1/2 code rate (or sometimes referred to as 1/2 encoding), and the latter is referred to as encoding at 1/4 code rate (or referred to as 1/4 encoding). do.

This is because when the 1/4 encoding is used, it has a higher error correction capability due to the higher code rate than the 1/2 encoding. For this reason, the data encoded at the 1/4 code rate in the group formatter 404 at the subsequent stage is allocated to the area where reception performance may deteriorate, and the data encoded at the 1/2 code rate is allocated to the area The effect of reducing the difference in performance can be obtained.

In this case, the block processor 403 may also receive signaling information including a transmission parameter, and the signaling information also performs 1/2 encoding or 1/4 encoding in the same manner as the mobile service data processing. . Then, the signaling information is regarded as mobile service data and processed.

Meanwhile, the group formatter 404 inserts the mobile service data output from the block processor 403 into a corresponding area in a data group formed according to a predefined rule, Data is also inserted into the corresponding area in the data group.

In this case, the data group may be divided into at least one layered area, and the type of mobile service data inserted into each area may vary according to characteristics of each layered area. For example, each region may be classified based on reception performance in a data group.

In the present invention, one data group is divided into A, B and C regions in the data structure before data deinterleaving. At this time, the group formatter 404 can allocate the mobile service data input by RS encoding and block coding to the corresponding area by referring to the transmission parameter.

The reason why the data group is divided into a plurality of regions is to differentiate each use. That is, a region where there is no interference of the main service data or a region where there is no interference can show robust reception performance than the region where no interference occurs. In addition, in case of applying a system for inserting and transmitting known data into a data group, when a long known data is inserted periodically in a mobile service data, a predetermined length of known data is stored in an area where there is no interference of main service data. It is possible to insert periodically. However, it is difficult to periodically insert the known data due to the interference of the main service data in the area where interference of the main service data exists, and it is also difficult to continuously insert the known data.

In addition to the encoded mobile service data output from the block processor 403, the group formatter 404 inserts an MPEG header position holder, an unstructured RS parity position holder, and a main service data position holder with respect to data deinterleaving at a later stage. do. The reason for inserting the main service data location holder is that there is an area where the mobile service data and the main service data are mixed between the data after the data interleaving. For example, the position holder for the MPEG header may be allocated in front of each packet when viewed from the output data after the data deinterleaving.

In addition, the group formatter 404 inserts known data location holders for inserting known data generated by a predetermined method or inserting known data later. In addition, a position holder for initializing the trellis encoding module 226 of the postprocessor 220 is inserted into the corresponding region. In one embodiment, the initialization data location holder may be inserted before the known data sequence.

At this time, the mobile service data size that can be inserted into one data group is determined by the size of the trellis initialization position holder, known data (or known data location holder), MPEG header location holder, RS parity location holder, It can be different.

The output of the group formatter 404 is input to the data deinterleaver 405. The data deinterleaver 405 receives data in the data group and the position holder output from the group formatter 404 as an inverse process of data interleaving Deinterleaves the packet and outputs it to the packet formatter 406.

The packet formatter 406 removes the main service data location holder and the RS parity location holder which have been allocated for deinterleaving among the deinterleaved input data, collects the remaining parts, and then stores the MPEG headers in the 4-byte MPEG header location holder. Insert

The packet formatter 406 may insert the known known data into the known data location holder when the known data location holder is inserted in the group formatter 404 or may insert the known data location holder It can be output without adjustment.

The packet formatter 406 then divides the data in the packet-formatted data group into mobile service data packets (ie, MPEG TS packets) in units of 188 bytes and provides them to the packet multiplexer 219.

The packet multiplexer 219 multiplexes the 188-byte mobile service data packet and the main service data packet output from the packet formatter 406 according to a predefined multiplexing method, and then post-processor 220. The data is output to the data randomizer 221. The multiplexing method can be adjusted by various parameters of the system design.

As one of the multiplexing methods of the packet multiplexer 219, a burst section may be provided on the time axis, and a plurality of data groups may be transmitted in the burst section, and only main service data may be transmitted in the non-burst section. In this case, the main service data may be transmitted in the burst period. In addition, the packet multiplexer 219 refers to a transmission parameter provided by the signaling information provider 218, for example, the number, period, etc. of data groups included in one burst with reference to information such as a burst size or a burst period. It can be seen.

In this case, the mobile service data and the main service data may be mixed in one burst period, and only the main service data exists in the burst period. Therefore, the main service data interval for transmitting the main service data exists in both the burst period and the non-burst period. In this case, the number of main data packets included in the main service data interval in the burst interval and the interval in the non-burst interval may be different from each other or may be the same.

When the mobile service data is transmitted in the burst structure as described above, the receiving system that receives only the mobile service data receives the data by turning on the power only in the burst period and turns off the power in the period in which only the main service data is transmitted, The power consumption of the receiving system can be reduced.

However, since the mobile service data group is multiplexed between main service data in the packet multiplexing process, the temporal location of the main service data packet is relatively moved. In the system target decoder (i.e., MPEG decoder) for main service data processing of the receiving system, only the main service data is received and decoded, and the mobile service data packet is recognized as a null packet.

Therefore, packet jitter occurs when the system target decoder of the receiving system receives the main service data packet multiplexed with the mobile service data group.

At this time, since there are several stage buffers for the video data in the system target decoder and the size thereof is quite large, the packet jitter generated by the packet multiplexer 219 is not a big problem in the case of video data. However, the size of the buffer for audio data of the system target decoder can be a problem because it is small.

That is, due to the packet jitter, an overflow or an underflow may occur in a buffer for a main service data of the receiving system, for example, a buffer for audio data.

Accordingly, the packet jitter reducer 214 readjusts the relative position of the main service data packet so that no overflow or underflow occurs in the buffer of the system target decoder.

Embodiments for rearranging the positions of the audio data packets of the main service data in order to minimize the influence on the operation of the audio buffer will be described. The packet jitter reducer 214 rearranges the audio data packets in the main service data interval so that the audio data packets of the main service can be located as uniformly as possible.

In the packet jitter reducer 214, a criterion for relocating an audio data packet of a main service is as follows. In this case, it is assumed that the packet jitter reducer 214 knows the multiplexing information of the packet multiplexer 219 at a later stage.

First, if there is one audio data packet in the main service data section in the burst section, for example, in the main service data section located between the two mobile service data groups, the audio data packet is placed in front of the main service data section If two or more exist, they are placed at the beginning and the end. If three or more exist, the first and the last are arranged, and the remaining are arranged at equal intervals therebetween.

Second, an audio data packet is arranged at the last position in the main service data section before the start of the burst section.

Third, after the burst period ends, the audio data packet is arranged first in the main service data section.

The packets which are not audio data are arranged in a space excluding the positions of the audio data packets in the input order.

Meanwhile, if the position of the main service data packet is relocated as described above, the corresponding PCR (Program Clock Reference) value should be modified accordingly. The PCR value is inserted into a specific area of the TS packet as a time reference value for matching the time of the MPEG decoder and transmitted. In an embodiment, the packet jitter reducer 214 also performs a function of PCR value correction.

The output of the packet jitter reducer 214 is input to a packet multiplexer 219. As described above, the packet multiplexer 219 multiplexes the main service data output from the packet jitter reducer 214 and the mobile service data output from the preprocessor 216 into a burst structure according to a preset multiplexing rule. Output to the data randomizer 221 of the processor 220.

If the input data is a main service data packet, the data renderer 221 performs rendering in the same manner as a conventional renderer. In other words, the synchronous bytes in the main service data packet are discarded and the remaining 187 bytes are randomly generated using internally generated pseudo random bytes, and then output to the RS encoder / unscrambler RS encoder 222.

However, if the input data is a mobile service data packet, the synchronization byte of the 4-byte MPEG header included in the mobile service data packet is discarded and the remaining 3 bytes are subjected to rendering, and the remaining mobile service data excluding the MPEG header And outputs it to the RS encoder / unscrambler RS encoder 222 without performing randomization. This is because the data renderer 401 has previously performed the randomization on the mobile service data. Randomization may or may not be performed on known data (or known data location holders) and initialization data location holders included in the mobile service data packet.

The RS encoder / unscrambler RS encoder 222 performs RS encoding on the data to be rendered or bypassed by the data randomizer 221, adds 20 bytes of RS parity, and then transmits the data to the data interleaver 223, . If the input data is a main service data packet, the RS encoder / unscrambler RS encoder 222 performs systematic RS coding in the same manner as in the existing broadcasting system to add 20 bytes of RS parity after 187 bytes of data. In the case of a mobile service data packet, a 20-byte RS parity obtained by performing unsystematic RS encoding is inserted at a parity byte position within the packet.

The data interleaver 223 is a convolutional interleaver on a byte basis.

The output of the data interleaver 223 is input to a parity substitution unit 224 and an unstructured RS encoder 225.

On the other hand, in order to convert the output data of the trellis encoder 226 located at the rear end of the parity substitution unit 224 into known data defined by an appointment at the transmitting / receiving end, initialization of the memory in the trellis encoder 226 . That is, the memory of the trellis encoder 226 must be initialized before the inputted known data sequence is Trellis encoded.

At this time, the beginning of the inputted known data sequence is not an actual known data but an initialized data position holder inserted in the group formatter 404. Therefore, a process of generating initialization data immediately before the input known data string is trellis encoded and replacing the corresponding trellis memory initialization data position holder is required.

The trellis memory initialization data is determined based on the memory state of the trellis encoder 226 and is generated. Also, it is necessary to recalculate the RS parity due to the influence of the replaced initialization data and to replace it with the RS parity output from the data interleaver 223.

Therefore, in the non-systematic RS encoder 225, the mobile service data packet including the initialization data location holder to be replaced with the initialization data is input from the data interleaver 223, and the initialization data is input from the trellis encoder 226 Receive. Then, the initialization data position holder of the input mobile service data packet is replaced with the initialization data, the RS parity data added to the mobile service data packet is removed, and the new unstructured RS parity is calculated and output to the parity substitution unit 225. The parity substitution unit 225 selects the output of the data interleaver 223 in the mobile service data packet and the output of the unstructured RS encoder 225 in the RS parity and outputs it to the trellis encoding unit 226. [ .

Meanwhile, the parity substitution unit 224 selects RS data and RS data output from the data interleaver 223 when a mobile service data packet including no initialization data location holder to be input or replaced is input, And outputs it to the trellis encoder 226.

The trellis encoder 226 performs 12-way interleaving on the data of each byte unit in units of symbols, performs trellis encoding on the data, and outputs the resultant data to the synchronous multiplexer 230.

The synchronous multiplexer 230 inserts the field sync and the segment sync into the output of the trellis encoder 226 and outputs it to the pilot inserter 241 of the transmitter 240.

The pilot inserted data in the pilot inserter 241 is modulated by a modulator 242 in a predetermined modulation scheme, for example, a VSB scheme, and then transmitted to each reception system via an RF up-converter 243.

Meanwhile, the mobile service multiplexer 150 and the transmitter 200 in the service multiplexer 100 should be closely interworked with each other. This is because the mobile service multiplexer 150 determines the transmission parameter used when transmitting data from the transmitter 200, but the data rate transmitted by the transmitter 200 is determined by this transmission parameter.

When the service multiplexer 100 transmits the mobile service data and the PSI / PSIP table for the mobile service together with the main service data and the PSI / PSIP table for the main service in TS packet units and is transmitted to the transmitter 200, The average data rate of the service is maintained as set by the service multiplexer 100.

However, if the de-multiplexer 211 of the transmitter 200 removes the filled null packet and divides it into a main service data packet and a mobile service data packet, the data rate of the mobile service data packet is changed every minute. Therefore, in order for the transmitter 200 to perform the transmission process at a constant data rate, the demultiplexed main service data packet is temporarily stored in the main data buffer 213 and then provided to the packet jitter reducer 214, and the mobile service. The data packet is temporarily stored in the mobile data buffer 215 and then provided to the pre-processor 216.

At this time, a case where mobile service data packets that are temporarily larger than the size of the mobile data buffer 215 may be accumulated in the mobile data buffer 215 may occur. This occurs mainly when the data rate of the mobile service data packet input to the mobile data buffer 215 is faster than the data rate of the mobile service data packet output from the mobile data buffer 215, which is called overflow. Sometimes. On the contrary, the amount of mobile service data packets temporarily accumulated in the mobile data buffer 215 is small, so that all mobile service data packets in the mobile data buffer 215 are discarded before the new mobile service data packets are entered into the mobile data buffer 215. Output to the preprocessor 216 may occur. This occurs mainly when the data rate of the mobile service data packet input to the mobile data buffer 215 is later than the data rate of the mobile service data packet output from the mobile data buffer 215, which is called underflow. Sometimes. However, when overflow or underflow occurs in the mobile data buffer 215, a problem may occur in service transmission through the transmitter 200. For example, if an overflow occurs, the new data may be overwritten before the data in the mobile data buffer 215 is transmitted, and the old data may be lost. On the contrary, when an underflow occurs, a large amount of irregularity from the transmitter 200 to the receiver is irregular. Sending null data can make reception control and decoding of the receiving system difficult.

In another case, the data rate of the mobile service input to the mobile service multiplexer 150 and the transmission data rate of the transmitter 200 may not exactly match. This is a case where the mobile service multiplexer 150 multiplexes the mobile service data without accurately supporting the data rate for each transmission mode of the transmitter 200. At this time, the mobile service multiplexer 150 generates the transmission parameter by controlling the PSI / PSIP generator 130 so that the mobile service data can be transmitted at a data rate closest to the output data rate according to the transmission mode of the transmitter 200. After the transmission to the transmitter 200. However, even in such a case, a problem may occur in service transmission through the transmitter 200 mentioned above.

In the present invention, in order to solve these problems, the transmitter 200 may temporarily adjust the transmission parameter to compensate for the data rate. A method of compensating the data rate by adjusting the transmission parameter includes, for example, a method of adjusting a burst period and a method of adjusting a burst size.

In another embodiment, the transmitter 200 may temporarily insert or remove null data packets temporarily to compensate for the data rate.

In this case, the data rate is adjusted in conjunction with the amount of data accumulated in the mobile data buffer 215.

FIG. 5 illustrates an example of an operation of the packet multiplexer 219 according to a specific embodiment of the present invention, and illustrates an embodiment in which data transmission is performed in burst units according to a transmission parameter.

5 shows an embodiment in which two types of mobile service data (for example, two mobile service programs) are multiplexed with main service data in burst units and transmitted. In FIG. 5, 118 mobile service data packets are gathered to form one data group, and 18 data groups are gathered to form one burst. That is, 18 data groups are transmitted in one burst.

For example, two burst intervals for both types of mobile services include 18 data groups, and each burst is repeated in 60 field periods.

In addition, one burst section includes 30 fields, among which a burst on section includes 18 fields and a burst off section includes 12 fields. That is, one field in the burst on period includes one data group. For example, as shown in FIG. 5, if one data group includes 118 data packets, the main service data packet may be transmitted in the remaining 194 data packet intervals in the corresponding field. This means that each field consists of 312 data segments, in which data in the data group is allocated to 118 segments, and main service data is allocated to 194 segments.

If only one type of mobile service is transmitted in FIG. 5, each burst section includes 18 data groups, and a repetition period of each burst corresponds to 30 fields.

In this case, a burst size of each mobile service or a transmission parameter applied by the preprocessor 216 may be applied differently for each service. As described above, the transmitter 200 in the form of PSI / PSIP is transmitted from the mobile service multiplexer 150. You can also tell.

As described above, when the transmitting system transmits mobile service data in a burst structure, the receiving system receives the corresponding service data by turning on the power only in the corresponding burst section including the desired service, and in the remaining sections, the power is turned off. The power consumption of the system can be reduced. In addition, the receiving system receives data by turning on the power during the burst on period including the data group in one burst period, and saving power by turning off the power during the burst off period.

Figure 6 shows an embodiment of a data rate compensation method by the transmitter of the present invention as a data structure, and shows an example of compensating the data rate by adjusting the burst size.

FIG. 6 shows an example in which the burst size is largely adjusted to output more than average mobile service data packets from the mobile data buffer 215. This may be applied when the data rate of the mobile service data packet input to the mobile data buffer 215 is faster than the data rate of the mobile service data packet output from the mobile data buffer 215.

In an embodiment of the present invention, the first and second thresholds are set in advance, and overflow occurs when the amount of data accumulated in the mobile data buffer 215 is greater than the first threshold, and underflow occurs when the second threshold is smaller than the second threshold. To be considered.

If the amount of data accumulated in the mobile data buffer 215 is between the first threshold value and the second threshold value, there is no need to compensate for the data rate. In this case, do not adjust the burst size.

If an overflow occurs, the burst size is increased so that more mobile service data packets than the average are output from the mobile data buffer 215. On the contrary, if an underflow occurs, the burst size is reduced so that fewer than average mobile service data packets are output from the mobile data buffer 215.

In this case, the setting of the first and second threshold values and the adjustment of the burst size are performed by the buffer controller 217. That is, the buffer controller 217 monitors the mobile data buffer 215 and adjusts the burst size among transmission parameters of the signaling information provider 218 when overflow or underflow occurs. The signaling information provider 218 transmits a transmission parameter including the adjusted burst size to a related block.

7 is a flowchart illustrating an embodiment of a data rate compensation method by a transmitter of the present invention, and shows an example of compensating a data rate by adjusting a burst size.

That is, the mobile service data packet demultiplexed by the demultiplexer 211 is temporarily stored in the mobile data buffer 215 and then output (step 501).

In this case, it is determined whether the amount of data accumulated in the mobile data buffer 215 is greater than the first threshold value (step 502). 215) and output (step 503). That is, while monitoring the amount of mobile service data packets accumulated in the mobile data buffer 215 and if the amount of packets accumulated in the mobile data buffer 215 is greater than a first threshold value, the associated transmission parameter is temporarily increased to increase the burst size. Adjust it. For example, if an overflow occurs while the current burst size is set to 18 data groups, the related transmission parameter of the signaling information provider 218 is adjusted such that the next burst size is 19 data groups as shown in FIG. do. In this case, since the burst period does not change, the burst on period in the corresponding burst period includes 19 fields, and the burst off period includes 11 fields.

The adjusted transmission parameters are provided to the preprocessor 216 and the packet multiplexer 219 in the transmitter 200 and also transmitted to the receiving system.

On the other hand, it is checked whether the amount of data accumulated in the mobile data buffer 215 is smaller than the second threshold (step 505). Output at 215 (step 506). This may increase the cumulative amount of mobile service data packets in the mobile data buffer 215.

That is, while monitoring the amount of mobile service data packets accumulated in the mobile data buffer 215, if the amount of packets accumulated in the mobile data buffer 215 is smaller than the second threshold value, the related transmission is temporarily reduced so that the burst size becomes small. Adjust the parameters. For example, if underflow occurs while the current burst size is set to 18 data groups, the related transmission parameter of the signaling information provider 218 is adjusted so that the next burst size is 17 data groups. In this case, since the burst period does not change, the burst on period in the corresponding burst period includes 17 fields, and the burst off period includes 13 fields.

The adjusted transmission parameters are provided to the preprocessor 216 and the packet multiplexer 219 in the transmitter 200 and also transmitted to the receiving system.

The preprocessor 216 performs preprocessing on the mobile service data packet according to the transmission parameter, and the packet multiplexer 219 outputs the packet jitter reducer 214 and the preprocessor 216 with reference to the adjusted burst size. Multiplex the output of the &lt; RTI ID = 0.0 &gt;

8 shows another embodiment of a data rate compensation method by the transmitter of the present invention as a data structure, and shows an example of compensating the data rate by adjusting a burst period.

FIG. 8 shows an example in which a burst period is shortened so that more than average mobile service data packets are output from the mobile data buffer 215. This may be applied when the data rate of the mobile service data packet input to the mobile data buffer 215 is faster than the data rate of the mobile service data packet output from the mobile data buffer 215.

In another embodiment of the present invention, the first and second thresholds are set in advance, and overflow occurs when the amount of data accumulated in the mobile data buffer 215 is greater than the first threshold, and underflow occurs when the second threshold is smaller than the second threshold. To be considered.

If the amount of data accumulated in the mobile data buffer 215 is between the first threshold value and the second threshold value, there is no need to compensate for the data rate. In this case, do not adjust the burst period.

If an overflow occurs, the burst period is shortened so that more than average mobile service data packets are output from the mobile data buffer 215. On the contrary, when an underflow occurs, the burst period is lengthened so that fewer than average mobile service data packets are output from the mobile data buffer 215.

In this case, the first and second thresholds are set and the burst period is adjusted by the buffer controller 217. That is, the buffer controller 217 monitors the mobile data buffer 215 and adjusts a burst period among transmission parameters of the signaling information provider 218 when an overflow or an underflow occurs. The signaling information provider 218 transmits the transmission parameter including the adjusted burst period to the related block.

9 is a flowchart illustrating another embodiment of a data rate compensation method by the transmitter of the present invention, and shows an example of compensating the data rate by adjusting a burst period.

That is, the mobile service data packet demultiplexed by the demultiplexer 211 is temporarily stored in the mobile data buffer 215 and then output (step 601).

In this case, it is checked whether the amount of data accumulated in the mobile data buffer 215 is greater than a first threshold value (step 602). Output at 215 (step 603). That is, while monitoring the amount of mobile service data packets accumulated in the mobile data buffer 215 and if the amount of packets accumulated in the mobile data buffer 215 is greater than a first threshold value, the burst parameter is temporarily shortened so that the burst period is shortened. Adjust it. For example, if an overflow occurs while the current burst period is set to 60 fields, as shown in FIG. 8, the related transmission parameter of the signaling information provider 218 is adjusted so that the next burst period is 59 fields. In this case, since the burst size does not change, the burst on interval in the corresponding burst includes 18 fields, and instead, the burst off interval includes 11 fields. The adjusted transmission parameters are provided to the preprocessor 216 and the packet multiplexer 219 in the transmitter 200 and also transmitted to the receiving system.

On the other hand, it is checked whether the amount of data accumulated in the mobile data buffer 215 is smaller than the second threshold (step 605). Output from the buffer 215 (step 606). That is, while monitoring the amount of mobile service data packets accumulated in the mobile data buffer 215, if the amount of packets accumulated in the mobile data buffer 215 is smaller than a second preset threshold, the related transmission is temporarily transmitted to increase the burst period. Adjust the parameters. For example, if underflow occurs while the current burst period is set to 60 fields, the next burst period adjusts the related transmission parameter of the signaling information provider 218 to be 61 fields. In this case, since the burst size does not change, the burst on section in the corresponding burst section includes 18 fields, and instead, the burst off section includes 13 fields. The adjusted transmission parameters are provided to the preprocessor 216 and the packet multiplexer 219 in the transmitter 200 and also transmitted to the receiving system.

The preprocessor 216 performs preprocessing on the mobile service data packet according to the transmission parameter, and the packet multiplexer 219 outputs the packet jitter reducer 214 and the preprocessor 216 with reference to the adjusted burst size. Multiplex the output of the &lt; RTI ID = 0.0 &gt;

FIG. 10 is a flowchart illustrating still another embodiment of a data rate compensation method by the transmitter of the present invention, and shows an example of compensating the data rate by inserting or adding null data. In the present invention, the null data packet inserted by the transmitter 200 will be referred to as a transmission null data packet to distinguish it from the filled null data packet inserted by the service multiplexer 100 to match the data rate. The filled null data packet is removed without being processed by the transmitter 200, but the transmitted null data packet inserted by the transmitter 200 is regarded as a mobile service data packet, processed, and then transmitted to the receiving system.

In addition, when the mobile service data input to the mobile service multiplexer 150 of the service multiplexer 100 is in the form of a packet, a null data packet may be inserted to match the amount of data during compression encoding. In this case, the inserted null data packet is regarded as a mobile service data packet by the service multiplexer 100 and the transmitter 200, processed, and then transmitted to the receiving system. Therefore, in the present invention, the null data packet inserted during the compression encoding will also be referred to as a transmission null data packet.

The A / V decoder of the receiving system removes the transmission null data packet among the input data and decodes only the mobile service data packet.

In this case, the insertion of the transmission null data packet is performed at the input terminal of the preprocessor 216 and the removal is performed at the input terminal of the mobile data buffer 215.

The method of inserting the transmission null data packet into the preprocessor 216 is applicable when the transmission data rate at the transmitter 200 is larger than the output data rate of the service multiplexer 100. Yes. In this case, the preprocessor 216 additionally receives the transmission null data packet as well as the mobile service data packet output from the mobile data buffer 215.

On the contrary, the elimination of the null data packet input to the preprocessor 216 may be applied when the output data rate of the service multiplexer 100 is greater than the transmission data rate at the transmitter 200. Yes. In this case, the transmission null data packet included in the mobile service data packets input to the mobile data buffer 215 is removed to adjust the input / output data rate of the mobile data buffer 215.

In another embodiment of the present invention, the first and second thresholds are set in advance, and when the amount of data accumulated in the mobile data buffer 215 is greater than the first threshold, overflow occurs. It is considered to have occurred.

The buffer controller 217 sets the first and second threshold values. When an underflow occurs, a transmission null data packet is generated and output to the preprocessor 216. When an overflow occurs, a mobile data buffer ( In an embodiment, the transmission null data packet inputted to 215 may be removed.

That is, the mobile service data packet demultiplexed by the demultiplexer 211 is temporarily stored in the mobile data buffer 215 and then output (step 701).

In this case, it is determined whether the amount of data accumulated in the mobile data buffer 215 is greater than a first threshold value (step 702). Enter data packets into the mobile data buffer 215 (step 703). That is, since the overflow occurs when the input data rate of the mobile data buffer 215 is greater than the output data rate and the amount of data accumulated in the mobile data buffer 215 is greater than the first threshold value, the overflow occurs. The I / O data rate of the mobile data buffer 215 is adjusted by removing some of the transmission null data packets among the mobile service data packets.

Also, it is checked whether the amount of data accumulated in the mobile data buffer 215 is smaller than a second threshold value (step 705). At the same time, a transmission null data packet is generated and output to the preprocessor 216 (step 706).

In this case, the data rate output from the mobile data buffer 215 is lowered in accordance with the data rate input to the mobile data buffer 215. The transmitted null data packet inserted in step 706 is regarded as a mobile service data packet by the preprocessor 216, processed, and then transmitted to the receiving system. The A / V decoder of the receiving system removes the transmission null data packet among the input data and decodes only the mobile service data packet.

As described above, the preprocessor 216 performs the preprocessing on the mobile service data packet according to the transmission parameter provided by the signaling information provider 218. In the packet multiplexer 219, the burst size and burst in the transmission parameter are performed. The output of the packet jitter reducer 214 and the output of the preprocessor 216 are multiplexed with reference to the period, and then transmitted in a burst structure (step 704).

According to an embodiment of the present invention, the signaling information including the transmission parameter may be allocated by inserting a certain area of the mobile service data packet or data group. In this case, the signaling information is treated the same as mobile service data in the preprocessor. Alternatively, the signaling information may be inserted by multiplexing with other data. For example, when multiplexing the known data with the mobile service data, the signaling information may be inserted instead of the known data at a position where the known data may be inserted, or may be mixed with the known data. Alternatively, the signaling information may be allocated by inserting a part of the unused area in the field sync segment of the transport frame. On the other hand, when the signaling information is inserted into the field sync segment area or the known data area and transmitted, since the reliability thereof is deteriorated when the signaling information passes through the transmission channel, one of the predefined patterns is inserted according to the signaling information. It is also possible. In this case, the receiving system may recognize the signaling information by performing a correlation operation between the received signal and the predefined patterns.

Until now, in the present invention, when the output data rate of the service multiplexer 100 and the transmission data rate of the transmitter 200 do not coincide, the transmitter 200 temporarily adjusts burst size adjustment, burst period adjustment, null data insertion or removal. Explains how to temporarily adjust the data rate. As another embodiment of the present invention, the data rate may be adjusted by combining one or more of the burst size adjustment, the burst period adjustment, and null data insertion or removal. For example, a burst period may be adjusted when an overflow occurs, and null data may be inserted when an underflow occurs.

11 is a block diagram illustrating a configuration of a receiving system according to an embodiment of the present invention.

The data received by the receiving system of FIG. 11 may include transmission null data inserted by the transmitter for data rate adjustment. In addition, the burst period, burst size, etc. in the transmission parameters received by the receiving system may not be fixed but may vary.

In addition, the reception system may improve reception performance by performing carrier synchronization recovery, frame synchronization recovery, channel equalization, etc. using known data information inserted into the mobile service data interval by the transmission system and transmitted.

To this end, the reception system according to the present invention includes a demodulator 801, an equalizer 802, a known data detector 803, a signaling information processor 804, a block decoder 805, and a data deformatter 806. RS frame decoder 807 and mobile service data de-randomizer 808. At this time, the output terminal of the mobile service data de-randomizer 808 may further include a null data removal unit 809 for removing the transmission null data inserted by the transmitting side. In addition, the reception system may further include a data deinterleaver 810, an RS decoder 811, and a main service data derandomizer 811.

That is, the frequency of a specific channel received through the tuner (not shown) is down converted to an intermediate frequency (IF) signal and input to the demodulator 801 and the known data detector 803.

The demodulator 801 performs automatic gain control, carrier recovery, and timing recovery on the input IF signal to generate a baseband signal and outputs the same to the equalizer 802 and the known data detector 803.

The equalizer 802 compensates for the distortion on the channel included in the demodulated signal and outputs it to the block decoder 805.

At this time, the known data detector 803 detects the known data position inserted by the transmitting side from the input / output data of the demodulator 801, that is, data before demodulation or data after demodulation is performed, A symbol sequence of known data generated at the position is output to the demodulator 801 and the equalizer 802. In addition, the known data detector 803 is configured to distinguish the mobile service data that has undergone additional encoding and the main service data that does not undergo additional encoding by the block decoder 805 at the transmitting side. Will output Although the connection state is not illustrated in the drawing of FIG. 9, the information detected by the known data detector 803 may be generally used in the reception system, and may be used in the data deformatter 806 and the RS frame decoder 807. have.

The demodulator 801 can improve demodulation performance by using the known data symbol string during timing recovery or carrier recovery. The equalizer 802 can also use the known data to improve equalization performance. . In addition, the equalization performance may be improved by feeding back the decoding result of the block decoder 805 to the equalizer 802.

On the other hand, if the data inputted to the block decoder 805 after channel equalization by the equalizer 802 is mobile service data in which both additional encoding and trellis encoding are performed at the transmitting side, trellis decoding and If additional decoding is performed and no additional encoding is performed and only trellis encoding is performed, only trellis decoding is performed. The data group decoded by the block decoder 805 is input to the data deformatter 806, and the main service data packet is input to the data deinterleaver 810.

That is, if the input data is main service data, the block decoder 805 may perform Viterbi decoding on the input data to output a hard decision value, or hard decision the soft decision value and output the result.

On the other hand, if the input data is mobile service data, the block decoder 805 outputs a hard decision value or a soft decision value with respect to the input mobile service data.

That is, if the input data is mobile service data, the block decoder 805 decodes the data encoded by the block processor and the trellis encoder of the transmission system. In this case, the RS frame coder of the preprocessor on the transmitting side becomes an external code, and the block processor and trellis coder can be regarded as one internal code.

In order to maximize the performance of the outer code at the time of decoding the concatenated code, the soft decision value should be output from the decoder of the inner code.

Therefore, the block decoder 805 may output a hard decision value for the mobile service data, but it may be better to output a soft decision value if necessary.

Meanwhile, the data deinterleaver 810, the RS decoder 811, and the main service data derandomizer 812 are blocks necessary for receiving main service data, and are required in a reception system structure for receiving only mobile service data. You may not.

The data deinterleaver 810 deinterleaves the main service data output from the block decoder 805 in the reverse process of the data interleaver on the transmitting side and outputs the main service data to the RS decoder 811.

The RS decoder 811 performs systematic RS decoding on the deinterleaved data, and outputs the decoded data to the main service data de-randomizer 812.

The main service data derandomizer 812 receives the output of the RS decoder 811 to generate a pseudo random byte identical to the transmitter's renderer, bitwise XORs it, and then uses an MPEG sync byte. Is inserted before each packet and output as a 188-byte main service data packet.

On the other hand, the data output from the block decoder 805 to the data formatter 806 is in the form of a data group. The data deformatter 806 stores the known data, trellis initialization data, the MPEG header, and the RS parity added from the RS encoder / unstructured RS encoder or unstructured RS encoder of the transmission system. It removes and outputs to RS frame decoder 807.

That is, the RS frame decoder 807 receives only RS coded and / or CRC coded mobile service data from the data deformatter 806.

On the other hand, since the signaling information processing unit 804 can know the configuration of the input data group, a transmission parameter containing information such as burst size and burst period from signaling information in the data group output from the equalizer 802 or the block decoder 805. Extract them. The extracted transmission parameter is then provided to the required block. If the mobile service is received by turning on the power only in the burst period, information such as the burst period and the burst size in the transmission parameter is also provided as a block (not shown) that controls the power supply.

The RS frame decoder 807 performs an inverse process in the RS frame encoder of the transmission system to correct errors in the RS frame, and then 1-byte MPEG synchronization that has been removed in the RS frame encoding process to the error corrected mobile service data packet. The byte is added and output to the mobile service data derandomizer 808.

The mobile service data derandomizer 808 performs derandomization corresponding to the reverse process of the data randomizer of the transmission system and outputs the received mobile service data, thereby obtaining mobile service data transmitted from the transmission system. Will be. In this case, if there is transmission null data inserted by the transmitter, only the mobile service data is output after the null data is removed by the null data removal unit 809. The null data removal unit 809 may be included in an A / V decoder that restores the compressed coded mobile service data to a state before compression coding.

The present invention described so far is not limited to the above-described embodiments, and can be modified by those skilled in the art as can be seen from the appended claims, and such modifications are the scope of the present invention. Belongs to.

INDUSTRIAL APPLICABILITY As described above, the digital broadcasting system and the data processing method according to the present invention are advantageous in that they are robust against errors when transmitting mobile service data through a channel and compatible with existing receivers. In addition, there is an advantage that mobile service data can be received without error even in a channel with ghost and noise more than the existing system.

Further, the present invention can provide robustness to the mobile service data and strongly cope with fast channel change by performing error correction coding and error detection coding on the mobile service data and transmitting the same.

When multiplexing the main service data and the mobile service data with the burst structure, the relative positions of the main service data packets are re-adjusted and multiplexed, thereby allowing a packet to be generated when the multiplexed main service data packet is received in the receiving system Jitter can be reduced.

In particular, the present invention may facilitate data rate adjustment by matching the data rates by temporarily adjusting the transmission parameters at the transmitter when a difference occurs between the output data rate of the service multiplexer and the transmission data rate of the transmitter.

The present invention is more effective when applied to portable and mobile receivers in which channel variation is severe and robustness to noise is required.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention.

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

Claims (22)

A signal generator for generating a data group including a first region, a second region, and a third region, Wherein the first and third regions comprise mobile data and main data position holders, and the second region is mobile data, known data sequences, trellis initialization data, and Motion Picture Experts Group (MPEG) header position holders. RS parity data position holders and transmission parameter data; A deinterleaver for deinterleaving the data group; Remove the RS parity data position holders and the main data position holders from the deinterleaved data group, replace the MPEG header position holders included in the deinterleaved data group with MPEG headers, and replace the mobile data, A packet formatter for outputting mobile data packets including the known data sequences, the trellis initialization data, the MPEG header and the transmission parameter data; A multiplexer for multiplexing the mobile data packets with main data packets including main data; An RS encoder for adding Reed-Solomon (RS) parity data to data included in the multiplexed mobile and main data packets; And And an interleaver for interleaving the multiplexed mobile and main data packets including the RS parity data, wherein the interleaver is a convolutional interleaver in bytes. delete The apparatus of claim 1, wherein the digital broadcast signal transmission apparatus And a trellis encoder for trellis encoding the interleaved mobile and main data packets, wherein the trellis encoder is initialized at each beginning of the plurality of known data sequences. A receiver configured to receive a digital broadcast signal including a data group having a first region, a second region, and a third region; Wherein the first region and the third region comprise mobile data and main data, and the second region comprises mobile data, known data sequences, MPEG headers, RS parity data and transmission parameter data; A deinterleaver for deinterleaving the RS parity data, the mobile data and the main data, wherein the deinterleaver is a convolutional deinterleaver in bytes; And And a decoder for decoding the digital broadcast signal. Creating a data group comprising a first region, a second region and a third region, Wherein the first and third regions comprise mobile data and main data position holders, and the second region is mobile data, known data sequences, trellis initialization data, MPEG header position holders, RS parity data position Holders and transmission parameter data; Deinterleaving the data group; Removing the RS parity data position holders and the main data position holders from the deinterleaved data group, replacing the MPEG header position holders included in the deinterleaved data group with MPEG headers, and replacing the mobile data, Outputting mobile data packets including the known data sequences, the trellis initialization data, the MPEG header and the transmission parameter data; Multiplexing the mobile data packets with main data packets including main data; Adding RS parity data to data included in the multiplexed mobile and main data packets; And Interleaving the multiplexed mobile and main data packets comprising the RS parity data, wherein the interleaving is convolutional interleaving in bytes. delete The method of claim 5, wherein the digital broadcast signal transmission data processing method Trellis encoding the interleaved mobile and main data packets, wherein trellis encoding is initialized at each beginning of the plurality of known data sequences. Receiving a digital broadcast signal comprising a data group having a first region, a second region and a third region, Wherein the first region and the third region comprise mobile data and main data, and the second region comprises mobile data, known data sequences, MPEG headers, RS parity data and transmission parameter data; Deinterleaving the RS parity data, the mobile data and the main data, wherein the deinterleaving is convolutional deinterleaving in bytes; And And decoding the digital broadcast signal. delete delete delete delete delete delete delete delete delete delete delete delete delete delete

Images