KR20100072451A - Method and apparatus for having variable error correction capability - Google Patents

Abstract

PURPOSE: A method and an apparatus for having variable error correction capability are provided to use stuff field of an MPEG-2 transport stream for error correction, thereby providing Reed-Solomon encoder of the various error correction capability without expansion of hardware. CONSTITUTION: A transmission error correction device(400) comprises a packet receiving unit(401), a field confirmation unit(402) and error correction processor(403). The packet receiving unit receives a packet of a TS(Transport Stream) from a broadcasting system. The field confirmation unit confirms stuff field from received packet. Based on the confirmed stuff field, the error correction processor corrects an error of broadcasting contents.

Description

METHOD AND APPARATUS FOR HAVING VARIABLE ERROR CORRECTION CAPABILITY}

The present invention relates to a transmission error correction apparatus and method, and more particularly, to correct a transmission error of broadcast content using a stuff byte of an MPEG-2 transport stream in a digital cable broadcasting system using a Reed Solomon code. An apparatus and method are provided.

The present invention is derived from the research conducted as part of the IT growth engine technology development project of the Ministry of Knowledge Economy and the Ministry of Information and Telecommunications Research and Development. Development of Multimedia Transmission Technology].

Digital Multimedia Broadcasting (DMB) receiver is a next-generation digital broadcasting receiver that can receive not only CD-quality high-quality audio service but also various additional data services such as traffic and stock information, as well as clear image quality during high-speed travel. The DMB system encodes various types of data such as video, audio, and additional data in the form of MPEG-4 data in accordance with MPEG-2 and MPEG-4 system technical standards to transmit high quality video and audio data. Different types of encoded data are sent in the form of MPEG-2 Transport Streams.

In satellite digital multimedia broadcasting, H.264 video compression technology for efficiently compressing video data in a channel having a limited bandwidth and transmission rate and MPEG-2 transport stream transmission technology for efficiently transmitting multimedia data are used. . That is, the satellite digital multimedia broadcasting transmitter compresses the image data using H.264 video compression technology, encodes the data, and multiplexes the data using the MPEG-2 transport stream transmission technology to transmit it to the satellite. The digital multimedia broadcasting receiver receiving the multiplexed MPEG-2 transport stream through the satellite demultiplexes it, decodes the image data extracted from the MPEG-2 transport stream for the desired program, and compresses the H.264 data. To display it.

A transmission error correction method according to an embodiment of the present invention aims to provide a Reed Solomon encoder having various error correction capabilities.

The transmission error correction method according to an embodiment of the present invention aims to provide a Reed Solomon encoder having various error correction capabilities without hardware expansion by using a stuff field of an MPEG-2 transport stream packet for error correction. .

In order to achieve the above object and solve the problems of the prior art, the transmission error correction method according to an embodiment of the present invention, the packet of the MPEG-2 transport stream (Moving Picture Expert Group-2 Transport Stream) from the broadcast system Receiving a message, identifying a stuff field from the received packet, and correcting an error of broadcast content based on the identified stuff field.

In the transmission error correcting apparatus according to an embodiment of the present invention, a packet receiving unit for receiving a packet of an MPEG-2 transport stream from a broadcasting system, a field checking unit for checking a stuff field from the received packet, and And an error correction processing unit that corrects an error of broadcast content based on the identified stuff field.

According to the present invention, it is possible to provide a Reed Solomon encoder having various error correction capabilities.

According to the present invention, by using the stuff field of an MPEG-2 transport stream for error correction, it is possible to provide a Reed Solomon encoder having various error correction capabilities without hardware extension.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a flowchart illustrating a transmission error correction method according to an embodiment of the present invention.

Referring to FIG. 1, the transmission error correction method according to an embodiment of the present invention receives a packet of an MPEG-2 Transport Stream (Moving Picture Expert Group-2 Transport Stream) from a broadcast system (S101).

Transport streams are used for channels, digital TV broadcasting, and transmission, where the probability of error is relatively high in the MPEG-2 system. The transport stream is divided into packets and provides a method for recovering a relatively complicated header and error in the packet, and includes a sync byte for separating the packets.

These packets are usually divided in units of 188 bytes, and are modulated for transmission over the terrestrial, satellite, and cable. For this modulation, it is necessary to identify a synchronization signal that separates the packets.

The MPEG-2 transport stream according to an embodiment of the present invention will be described in detail with reference to FIG. 2.

2 is a view for explaining the format of the MPEG-2 transport stream 200 according to an embodiment of the present invention.

The MPEG-2 transport stream 200 is fixed to 188 bytes in total and includes a packet header field 201 of 4 bytes and a payload field of 184 bytes in detail.

The packet header field 201 is allocated to 4 bytes and may be divided into a prefix field and an adaptation field. The packet header field 201 includes synchronization information serving as a start code of a packet.

The payload field also includes a point field 202 of 1 byte, a MAC frame field 203 of 34 bytes, and stuff fields 204 and 205 of 149 bytes.

The MAC frame field 203 may include a synchronization message, and the stuff fields 204 and 205 may further include a variable Reed Solomon field 204 of 1 byte.

The variable Reed Solomon field 204 is a field for implementing a Reed Solomon encoder having various error correction capabilities using a part of a stuff field of an existing MPEG-2 transport stream.

Specifically, on the basis of the variable Reed Solomon value recorded in the variable Reed Solomon field 204, the number of shift registers to be used based on the polynomial stored in the memory block is expanded and reduced so that a desired Reed Solomon encoder is desired. It can have error correction capability. As a result, as the error correction capability of the Reed Solomon encoder changes, the number of total shift registers and the structure of the linear feedback shift register (LFSR) need not be changed every time.

Referring back to FIG. 1, according to an embodiment of the present invention, a transmission error correction method checks a stuff field from the received packet (S102) and based on the checked stuff field, The error is corrected (S103).

Specifically, the transmission error correction method according to an embodiment of the present invention, the error correction capability value of the Reed Solomon encoder is determined from the identified stuff field, and according to the determined error correction capability value of the Reed Solomon encoder By activating / deactivating at least one shift register, an error of broadcast content may be corrected through a Reed Solomon encoder having various error correction capabilities.

As a result, by using the transmission error correction method according to an embodiment of the present invention, it is possible to provide a Reed Solomon encoder having various error correction capabilities. In addition, by using the stuff field of the MPEG-2 transport stream for error correction, it is possible to provide a Reed Solomon encoder having various error correction capabilities without hardware extension.

That is, the transmission error correction method controls the operation of the Reed Solomon encoder based on the variable Reed Solomon field included in the MPEG-2 transport stream, without changing the hardware to be determined according to the error correction capability value of the Reed Solomon code. The error of the broadcast content can be corrected.

More specifically, the transmission error correction method according to an embodiment of the present invention checks the variable Reed Solomon field of the stuff field, and checks the variable Reed Solomon value stored in the variable Reed Solomon field. The error of the broadcast content may be corrected based on the determined variable Reed Solomon value.

3 is a flowchart illustrating a method of correcting an error according to an embodiment of the present invention.

Hereinafter, the step of correcting an error in step S103 of FIG. 1 will be described in more detail.

First, in order to correct an error of the broadcast content, the transmission error correction method according to an embodiment of the present invention checks the variable Reed Solomon value through the variable Reed Solomon field included in the stuff field (S301).

Next, the transmission error correction method determines the error correction capability value of the Reed Solomon encoder based on the identified variable Reed Solomon value (S302). For example, if the variable Reed Solomon value is "00001000", an error correcting capability value required by the Reed Solomon encoder may be interpreted as a maximum of eight.

The transmission error correction method generates an enable signal for determining activation / deactivation of at least one shift register of the Reed Solomon encoder based on the determined error correction capability value (S303).

That is, in the transmission error correction method, if the error correction capability value required by the Reed Solomon encoder has a maximum value of 8, the variable Reed Solomon value is set to "00001000", and an error for operating the Reed Solomon encoder according to the set value A T value, which is a correction capability value, and an enable signal at that time may be generated and input to the Reed Solomon encoder.

In addition, the transmission error correction method controls activation / deactivation of the shift register based on the generated enable signal (S304).

When the enable signal is input to the Reed Solomon encoder, a transmission error correction method using a Reed Solomon encoder having various error correction capabilities may be implemented by controlling activation / deactivation of shift registers based on the enable signal. .

4 is a block diagram illustrating a transmission error correction apparatus 400 according to an embodiment of the present invention.

The transmission error correction apparatus 400 includes a packet receiver 401, a field checker 402, and an error correction processor 403.

The packet receiver 401 receives a packet of an MPEG-2 transport stream from a broadcast system.

In a channel of an MPEG-2 system with a relatively high probability of error occurrence, a transport stream may be used for digital TV broadcasting and transmission purposes.

For example, the transmission error correction apparatus 400 according to an embodiment of the present invention may be applied to a DMB system. The DMB system encodes various types of data such as video, audio, and additional data in the form of MPEG-4 data according to the MPEG-2 and MPEG-4 system technical standards to transmit high quality video data and audio data. In addition, the encoded data can be transmitted in the form of MPEG-2 transport stream.

In addition, the MPEG-2 transport stream may be divided into a plurality of packetized element streams (PES), and the PES is an audio PES, a video PES, an object descriptor (OD) PES, and a binary format for BIFS. Scene) PES may be included. In this case, the packet receiver 401 may also perform a task of decoding the divided PES.

The field identification unit 402 confirms a stuff field from the received packet.

In a typical MPEG-2 transport stream, a packet header field of 4 bytes and a payload field of 184 bytes may be included, and the stuff field may be included in the payload field.

The error correction processing unit 403 corrects the error of the broadcast content based on the checked stuff field.

The field checking unit 402 according to an embodiment of the present invention checks the variable Reed Solomon field value from the stuff field, and for this purpose, the error correction processor 403 based on the determined Reed Solomon field value. The enable signal may be determined.

The enable signal can change the error correction capability of the Reed Solomon encoder.

To this end, the error correction processing unit 403 includes a Reed Solomon encoder for varying an error correction capability value based on the identified stuff field, and processing an error of the broadcast content according to the variable error correction capability value. can do.

5 is a block diagram illustrating a Reed Solomon encoder 500 according to an embodiment of the present invention.

The Reed Solomon encoder 500 according to an embodiment of the present invention includes a memory bank 510, at least one shift register 520, and an adder 530. In addition, the switch 540 may further include an input of the memory word and the code word.

이며, 에러정정능력 값은

에 의해 결정될 수 있다. 이러한 에러정정능력 값은 리드 솔로몬 부호기(500)의 활성화된 시프트 레지스터(520)의 개수에 따라 결정될 수 있는데, 상기 인에이블 신호는 시프트 레지스터들의 동작을 활성화/비활성화 중에서 어느 하나로 동작하게 함으로써, 상기 에러정정능력 값을 결정할 수 있다.According to one embodiment of the present invention, the Reed Solomon encoder 500 is defined as a Gallois Field and is represented by a Reed Solomon code of (n, k). N represents the length of the coded block and k represents the length of the message in the coded block. Also, the minimum distance for the Reed Solomon code is

The error correction capability value is

Can be determined by. The error correction capability value may be determined according to the number of activated shift registers 520 of the Reed Solomon encoder 500. The enable signal may be operated by enabling or disabling the operation of the shift registers. The correction capability value can be determined.

For example, if the variable Reed Solomon field value of the stuff field is set to "00001000", the error correcting capability value t required by the Reed Solomon encoder 500 is determined to be 8, and the value of the variable Reed Solomon field value is determined. Based on the error correction capability value and the enable signal are generated together. Accordingly, the memory bank 510 of the Reed Solomon encoder 500 may determine the number of shift registers 520 that are activated according to the enable signal.

In addition, the adder 530 sums the outputs of the shift register 520.

As a specific example, since the Reed Solomon code of the Reed Solomon encoder 500 according to an embodiment of the present invention is defined in the Galoa field, a primitive polynomial is required for this purpose and is represented by Equation 1 below.

[Equation 1]

If the message of length k taken from the galoa field is expressed in k-1 order polynomial form, it is expressed as [Equation 2], and the constructor polynomial for generating Reed Solomon code can be expressed as [Equation 3]. have.

[Equation 2]

&Quot; (3) "

In Equation 3, a is a primitive circle of a primitive polynomial, and a positive integer b is a base value of the generator polynomial and has a value of 0 in the Reed Solomon encoder 500.

를 곱한 후 [수학식 3]의 생성다항식인 g(x)로 나누면 [수학식 4]와 같다.Generalizing this, the message polynomial is the same as [Equation 2] mentioned above, so the message polynomial m (x)

Multiply by and divide by g (x), the polynomial of Equation 3, as shown in Equation 4.

[Equation 4]

In this equation, q (x) is a quotient polynomial, p (x) represents a residual polynomial, and the order of p (x) is smaller than n-k. Accordingly, a code polynomial corresponding to m (x) may be finally determined by Equation 5.

[Equation 5]

와 같은 벡터형태로도 표현할 수 있다.Where the sign polynomial

It can also be expressed in a vector form such as

As a result, the Reed Solomon encoder 500 stores the symbols for each of the generated polynomials according to the (n, k) value required for the Reed Solomon code in the memory bank 510 according to the identified error correctability value. In addition, the memory bank 510 determines activation and deactivation of at least one shift register 520 according to the enable signal to determine the error correction capability of the Reed Solomon encoder 500.

According to the determined error correcting ability, the output of the shift register 520 is summed up through the adder 530, and finally the sign polynomial of Equation 5 can be used for error correction.

As a result, using the transmission error correction apparatus according to an embodiment of the present invention, it is possible to provide a Reed Solomon encoder having various error correction capabilities without hardware extension.

The transmission error correction method according to the present invention can be implemented in the form of program instructions that can be executed by various computer means and recorded in a computer readable medium. The computer readable medium may include program instructions, data files, data structures, etc. alone or in combination. Program instructions recorded on the media may be those specially designed and constructed for the purposes of the present invention, or they may be of the kind well-known and available to those having skill in the computer software arts. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tape, optical media such as CD-ROMs, DVDs, and floppy disks. Magneto-optical media, and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine code generated by a compiler, but also high-level language code that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

As described above, the present invention has been described by way of limited embodiments and drawings, but the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains various modifications and variations from such descriptions. This is possible.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the claims below but also by the equivalents of the claims.

1 is a flowchart illustrating a transmission error correction method according to an embodiment of the present invention.

2 is a view for explaining the format of an MPEG-2 transport stream according to an embodiment of the present invention.

3 is a flowchart illustrating a method of correcting an error according to an embodiment of the present invention.

4 is a block diagram illustrating a transmission error correction apparatus according to an embodiment of the present invention.

5 is a block diagram illustrating a Reed Solomon encoder according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

400: transmission error correction device

401: packet receiving unit

402: field confirmation unit

403: error correction processing unit

Claims (10)

Receiving a packet of an MPEG-2 Transport Stream from a broadcast system; Identifying a stuff field from the received packet; And Correcting an error of broadcast content based on the identified stuff field Transmission error correction method comprising a. The method of claim 1, The packet of the MPEG-2 transport stream includes a packet header field, a point field, a MAC frame field, and a stuff field. The method of claim 2, The stuff field includes a variable Reed Solomon field, Based on the identified stuff field, the step of correcting the error of the broadcast content, Identifying the variable Reed Solomon field in the identified stuff field; Checking a variable Reed Solomon value of the identified Reed Solomon field; And Correcting an error of the broadcast content based on the identified variable Reed Solomon value Transmission error correction method comprising a. The method of claim 3, The step of correcting the error of the broadcast content, Controlling an operation of a Reed Solomon encoder to correct an error of the broadcast content; Transmission error correction method comprising a. The method of claim 4, wherein The step of controlling the operation of the Reed Solomon encoder to correct the error of the broadcast content, Determining an error correction capability value of the Reed Solomon encoder based on the variable Reed Solomon value Transmission error correction method comprising a. The method of claim 5, The step of controlling the operation of the Reed Solomon encoder to correct the error of the broadcast content, Generating an enable signal that determines activation / deactivation of at least one shift register of the Reed Solomon encoder based on the determined error correction capability value. Transmission error correction method further comprises. A packet receiver for receiving a packet of an MPEG-2 transport stream from a broadcasting system; A field checking unit for checking a stuff field from the received packet; And An error correction processor that corrects an error of broadcast content based on the identified stuff field Transmission error correction apparatus comprising a. The method of claim 7, wherein The error correction processing unit, And a Reed Solomon encoder for varying an error correction capability value based on the identified stuff field and processing an error of the broadcast content according to the variable error correction capability value. The method of claim 8, The Reed Solomon encoder is A memory bank for generating an enable signal; At least one shift register configured to maintain at least one of activation and inactivation in accordance with the enable signal; And An adder for summing outputs of the shift registers; Transmission error correction apparatus comprising a. The method of claim 8, The field identification unit verifies a variable Reed Solomon field value from the stuff field, And the error correction processor determines the enable signal based on the identified variable Reed Solomon field value.

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