KR102014710B1 - Apparatus and method for transmitting and receiving packet in broadcasting and communication system - Google Patents

Abstract

According to an embodiment of the present disclosure, in a method of transmitting a packet by a signal transmission apparatus in a broadcasting and communication system, a forward error correction (FEC) parity packet and an FEC source packet Generating a FEC packet comprising a; and transmitting the FEC packet to a signal receiving apparatus, wherein the FEC parity packet includes a parity block and a plurality of parity subblocks based on a source block; The plurality of parity subblocks are generated by encoding information subblocks generated from a plurality of source sub-blocks using an FEC encoding scheme, and the plurality of source subblocks are generated in the source block. Generation using second source payloads selected from among the included first source payloads based on a preset source subblock generation method. And the FEC source packet is generated using the source block.

Description

Packet transmission / reception apparatus and method in broadcasting and communication system {APPARATUS AND METHOD FOR TRANSMITTING AND RECEIVING PACKET IN BROADCASTING AND COMMUNICATION SYSTEM}

The present invention relates to an apparatus and method for transmitting / receiving packets in a broadcasting and communication system, and more particularly, to an apparatus and method for transmitting / receiving packets using a source sub-block in a broadcasting and communication system. will be.

Broadcast and communication systems, for example, broadcast and communication systems, such as the Moving Picture Experts Group (MPT) Media Transport (MPT) system, are known as High Definition (HD) content, ultra high resolution ( Ultra High Definition: Provides a variety of high-capacity content, such as UHD (hereinafter referred to as "UHD") content.

In the broadcast and communication systems, data congestion is intensifying on the network due to the diversification of contents and the increase of high-capacity contents such as HD contents and UHD contents. Due to this situation, the content transmitted by the signal transmission device, for example, host A, is not normally delivered to the signal reception device, for example, Host B, and part or all of the content transmitted by the signal transmission device is routed. The situation is lost in.

On the other hand, since data is generally transmitted in packet units, data loss occurs in transmission packet units. As a result, if a transmission packet is lost on the network, the signal receiving apparatus cannot receive the lost transmission packet, and thus cannot know the data included in the lost transmission packet. Therefore, various types of inconveniences such as deterioration of audio quality, deterioration of image quality of video, broken screen, missing subtitles, and loss of files may be caused.

Therefore, there is a need for a method for recovering data loss generated on a network for this reason.

As such, when data is lost on the network, one of the ways of supporting the recovery of the lost data in the signal receiving apparatus is a preset number of which may have various lengths called a source packet. A source block is composed of data packets, and forward error correction (FEC, hereinafter referred to as 'FEC') encoding is performed such as parity data or repair packet. The recovery information is added to the source block.

In this manner, when the signal receiving apparatus detects that a data loss has occurred, the signal receiving apparatus may perform a decoding operation by using the recovery information. In this case, packets including a plurality of contents requiring different transmission reliability may be included in one source block. In this case, if the amount of recovery packets is determined based on the packets requiring the highest transmission reliability for one source block, the packets requiring the lower transmission reliability are overprotected to reduce the efficiency of the network. On the contrary, when the amount of repair packets is determined based on the packet requiring the lowest transmission reliability for one source block, the packet requiring the high transmission reliability cannot be recovered.

However, in the current broadcast and communication system, there is no specific proposal for a method for efficiently recovering data loss while considering transmission reliability of packets included in a source block.

Accordingly, there is a need for a method of efficiently recovering data loss while efficiently considering transmission reliability of packets included in a source block in a broadcasting and communication system.

The present invention provides a method and apparatus for transmitting / receiving a packet in a broadcasting and communication system.

The present invention also provides a method and apparatus for transmitting / receiving a packet using a source sub-block in a broadcasting and communication system.

The present invention also provides a packet transmission / reception method and apparatus for increasing data recovery efficiency in a broadcasting and communication system.

The present invention also provides a packet transmission / reception method and apparatus capable of obtaining efficient transmission reliability in a broadcasting and communication system.

Method according to an embodiment; A method for transmitting a packet in a broadcast and communication system, the method comprising: generating an FEC packet including a forward error correction (FEC) parity packet and an FEC source packet And transmitting the FEC packet to a signal receiving apparatus, wherein the FEC parity packet includes a parity block and a plurality of parity subblocks based on a source block, and the plurality of parity subblocks The information subblocks generated from the two source sub-blocks are encoded by using an FEC encoding scheme, and the plurality of source subblocks are generated from among first source payloads included in the source block. The FEC source packet is generated using second source payloads selected based on a preset source subblock generation method. Characterized by the generated by using the source block.

The present invention has the effect of enabling the transmission and reception of packets using source subblocks in broadcast and communication systems.

In addition, the present invention has the effect of enabling the packet transmission / reception to increase the data recovery efficiency in broadcast and communication systems.

In addition, the present invention has the effect of enabling the packet transmission / reception capable of obtaining efficient transmission reliability in a broadcast and communication system.

1 is a diagram schematically showing the structure of a broadcasting and communication system according to an embodiment of the present invention;
2 is a view schematically showing an example of an internal structure of the FEC coding block 102 of the signal transmission apparatus 100 of FIG. 1 according to an embodiment of the present invention.
3 is a diagram schematically illustrating a process of generating a source block in the source block generator 201 of FIG. 2.
4 is a diagram schematically showing another example of the internal structure of the FEC coding block 102 of the apparatus 100 for transmitting signals according to an embodiment of the present invention.
5 is a diagram schematically illustrating an example of a process of generating a source subblock of the source subblock generator 402 of FIG. 4.
FIG. 6 schematically illustrates another example of a source subblock generation process of the source subblock generator 402 of FIG. 4.
FIG. 7 schematically illustrates an internal structure of an FEC decoding block 113 of the signal receiving apparatus 110 of FIG. 1 according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

The present invention proposes an apparatus and method for transmitting / receiving packets in a broadcasting and communication system.

The present invention also proposes an apparatus and method for transmitting / receiving a packet using a source sub-block in a broadcasting and communication system.

The present invention also proposes a packet transmission / reception apparatus and method for increasing data recovery efficiency in a broadcasting and communication system.

In addition, the present invention proposes a packet transmission / reception apparatus and method capable of obtaining efficient transmission reliability in a broadcast and communication system.

Embodiments of the present invention to be described below will be referred to as High Definition (HD) contents, Ultra High Definition (UHD), or 'UHD' through a network. Data loss in all electronic devices such as mobile phones, TVs, computers, copyboards, tablets, and e-books that can provide a variety of multimedia services, such as video conferencing / calls, as well as high content content We propose a packet transmission / reception apparatus and method for efficient recovery.

In particular, in the embodiments of the present invention, when a forward error correction (FEC) method is applied to data packets, a source block may be a plurality of source subblocks. We propose a packet transmission / reception apparatus and method which can be divided into source sub-blocks, and efficiently generate an information block and an information subblock to improve FEC decoding performance or increase transmission efficiency. .

Meanwhile, although embodiments of the present invention do not describe a specific FEC coding scheme, in the embodiments of the present invention, the FEC coding scheme is Reed-Solomon (RS, hereinafter referred to as “RS”). Code, Low Density Parity Check (LDPC, hereinafter referred to as “LDPC”) Code, Turbo Code, Raptor Code, RaptorQ Code, XOR (Single Parity-Check) Note that it is not limited to a specific FEC coding scheme such as Code, Pro-MPEG (Moving Picture Experts Group) FEC code, or the like.

1 is a diagram schematically illustrating a structure of a broadcasting and communication system according to an embodiment of the present invention.

Referring to FIG. 1, the broadcasting and communication system includes a signal transmitting device 100 and a signal receiving device 110.

The signal transmission apparatus 100 performs a protocol A processing block 101 corresponding to protocol A corresponding to a higher order protocol of forward error correction (FEC, hereinafter referred to as 'FEC'). ), A FEC encoding block 102, a protocol B processing block 103 and a transmitter physical layer processing block 104 that perform a protocol B processing operation corresponding to protocol B corresponding to the FEC sub-protocol.

The protocol A processing block 101 performs a protocol A processing operation on the transmission data to generate source payloads 130 and converts the generated source payloads 130 into the FEC coding block. Output to (102). The FEC encoding block 102 configures a source block including at least one source payload, and performs parity payloads (FEC encoding operation) corresponding to a preset FEC encoding scheme with respect to the configured source block. 131).

In addition, the FEC encoding block 102 configures an FEC source packet by adding FEC headers 132 to the source payloads 130, and converts the configured FEC source packet to the protocol B processing block 103. To pass. Here, the FEC source packet indicates an FEC packet including a source payload and an FEC header.

The FEC encoding block 102 configures an FEC parity packet by adding the FEC header 132 to the parity payloads 131, and transfers the configured FEC parity packet to the protocol B processing block 103. . Here, the FEC parity packet indicates an FEC packet including a parity payload and an FEC header. Here, one FEC parity packet may include a plurality of parity payloads, and for convenience of description, it is assumed that one FEC parity packet includes one parity payload.

The protocol B processing block 103 generates a protocol B signal by performing a protocol B processing operation corresponding to protocol B on the FEC source packet or the FEC parity packet transmitted from the FEC encoding block 102, and generates the protocol B signal. Deliver a signal to the transmitter physical layer processing block 104.

The transmitter physical layer processing block 104 converts the protocol B signal received from the protocol B processing block 103 into a physical layer signal suitable for physical layer transmission, and converts the converted physical layer signal into the signal receiving apparatus ( 110).

Meanwhile, various processing blocks may exist between the protocol B processing block 103 and the transmitter physical layer processing block 104 in FIG. 1, and in FIG. 1, the protocol B processing block 103 and the transmitter are illustrated in FIG. 1. Detailed descriptions of various processing blocks that may exist between the physical layer processing blocks 104 will be omitted.

The apparatus 110 for receiving signals 110 includes a receiver physical layer processing block 111, a protocol B processing block 112 and a FEC decoding block 113 for performing a protocol B processing operation corresponding to protocol B corresponding to an FEC sub-protocol. And a protocol A processing block 114 for performing a protocol A processing operation corresponding to protocol A corresponding to the FEC higher protocol.

The receiver physical layer processing block 111 converts the physical layer signal received from the signal transmitting apparatus 100 to the signal receiving apparatus 110 through the transmission channel 120 into a protocol B signal, and converts the converted protocol. The B signal is passed to the protocol B processing block 112. As described in the signal transmission apparatus 100, various processing blocks may exist between the protocol B processing block 112 and the receiver physical layer processing block 111, and the protocol B processing block 112 and the receiver may be present. Detailed descriptions of various processing blocks existing between the physical layer processing blocks 111 will be omitted.

The protocol B processing block 112 generates a protocol B signal by performing a protocol B processing operation on a physical layer signal received by the protocol B processing block 112, and then converts the protocol B signal into the FEC decoding block ( 113). Here, the protocol B signal may be an FEC packet, that is, an FEC source packet or an FEC parity packet. At this time, some of the FEC packets transmitted by the signal transmission apparatus 100 are lost due to congestion of the network and the effects of an error occurring in the physical layer, and thus cannot be delivered to the FEC decoding block 113. The FEC decoding block 113 detects source payloads transmitted from the signal transmission apparatus 100 by performing an FEC decoding operation on the FEC packet transmitted from the protocol B processing block 112, and detects the detected source. Deliver payloads to the Protocol A processing block 114. The protocol A processing block 114 detects transmission data by performing a protocol A processing operation on the source payloads received from the FEC decoding block 113.

1 illustrates a structure of a broadcasting and communication system according to an embodiment of the present invention. Next, referring to FIG. 2, an internal structure of the FEC coding block 102 of the signal transmission apparatus 100 of FIG. 1 is described. An example will be described.

FIG. 2 is a diagram schematically illustrating an example of an internal structure of the FEC coding block 102 of the signal transmission apparatus 100 of FIG. 1 according to an embodiment of the present invention.

Referring to FIG. 2, the FEC encoding block 102 includes a source block generator 201, an information block generator 202, a parity block generator 203, an FEC parity packet generator 204, and an FEC source packet generator. 205.

When the source payloads 221 are input, the source block generator 201 configures the source payloads 221 as a source block and transfers the source payloads 221 to the information block generator 202 and the FEC source packet generator 205. do. In this case, the number of source payloads 221 included in the source block may be changed, and the length of each of the source payloads 221 may be different. A detailed description of the number of source payloads 221 and the length of the source payloads 221 included in the source block will be omitted.

The information block generator 202 inputs a source block output from the source block generator 201 and has a preset width T in which source payloads 221 included in the source block are preset. The information word block 211 is generated by arranging them sequentially in a two-dimensional array form, and the generated information word block 211 is output to the parity block generator 203. Here, each row included in the two-dimensional array is an information payload 222, and the width T is 'payload size'. In this case, the payload size may be typically expressed in units of bytes or bits.

The parity block generator 203 inputs the information word block 211 output from the information block generator 202 and performs an FEC encoding operation on the information block 221 to perform the parity block 212. After generation, the parity block 212 is passed to the FEC parity packet generator 204. The parity block 212 includes a parity payload 223 having the same size as that of the information payload 222.

The FEC parity packet generator 204 generates FEC parity packets by adding an FEC header 224 to each of the parity payloads 223 included in the parity block 212 output from the parity block generator 203. In addition, an FEC parity packet block 213 including the generated FEC parity packets is generated. The FEC parity packet generator 204 then outputs the FEC parity packet block 213 to the protocol B processing block 103.

Meanwhile, the FEC source packet generator 205 generates the FEC source packets by adding the FEC header 224 to each of the source payloads 221 included in the source block output from the source block generator 201. The generated FEC source packets are generated by the FEC source packet block 214. The FEC source packet generator 205 then outputs the FEC source packet block 214. In this case, the FEC header added to each of the FEC source packet and the FEC parity packet may have the same form or may have a different form.

2 illustrates an example of an internal structure of the FEC coding block 102 of the signal transmission apparatus 100 of FIG. 1 according to an embodiment of the present invention. Next, the source block of FIG. 2 will be described with reference to FIG. 3. A process of generating a source block in the generator 201 will be described.

FIG. 3 is a diagram schematically illustrating a process of generating a source block in the source block generator 201 of FIG. 2.

Referring to FIG. 3, the source block generator 201 divides a two-dimensional array having a symbol size T into m regions in units of T / m columns. It should be noted that the source block generation process illustrated in FIG. 3 is a source block generation process when m is 4 days (m = 4). Here, in the case where the symbol size T is not a multiple of m, the two-dimensional array includes regions each having [T / m] + 1 columns and regions each having [T / m] columns. Include. Here, for any real number A, [A] means a maximum integer less than or equal to A.

The regions each containing [T / m] + 1 columns and the regions each containing [T / m] columns are defined by a predetermined appointment between the signal transmission device and the signal receiving device, or each You can list the number of columns for the region of. The predetermined appointment is, for example, assuming that the remainder of T divided by m is n (n <m), and the first n regions are divided into [T / m] +1 columns, and the remaining mn Regions can be defined as being divided into [T / m] columns. In addition, the number of columns included in each region may be arbitrarily set differently according to the promise of the signal transmitting apparatus and the signal receiving apparatus, in addition to the regular region division scheme as described above.

On the other hand, if necessary, the source block generator 201 may identify a flow identifier (ID) (hereinafter, referred to as "ID"), for example, a user datagram protocol (UDP). Packet information such as flow ID and information 302 indicating the length of the source payload are added to the source payload. Here, each of the packet payload information, that is, the UDP pay ID 301 and the source payloads to which the source payload length information 302 is added, has a symbol size starting from the first column of the first row. It is arranged in sequence not to exceed T.

In this case, the source block generator 201 may perform additional information, that is, the last data of the source payload in the last row in which any source payload added by the packet characteristic information 301 and the source payload length information 302 is disposed. The remaining part in the area to which is allocated is always assigned (or set) to a predetermined value. Here, the predetermined value may be set to a value of "0" for convenience, but it should be noted that the predetermined value is not necessarily set to a value of "0". For example, in FIG. 3, since the last data of the second source payload is allocated to the second of four areas, the source block generator 201 may set the remaining portion 305 of the second area to “0”. Assigns the value ”. For convenience of description, the packet characteristic information 301 and the source payload length information 302 will be referred to as "additional information."

Also, after one source payload appended with the additional information is placed, the next source payload to be placed next is always the starting point of the next area of the area where the last data is allocated in the last row where the previous source payload is placed. Is placed from. In other words, all source payloads should be placed from the beginning of a region. For example, in FIG. 3 the second source payload starts to be placed from the beginning of the third region following the portion 305 assigned the value "0". Hereinafter, for the convenience of description, it is referred to as "zero padding" to be assigned a value of "0". If a zero-padded portion, such as the zero-padded portion 306 of the fourth source payload, is allocated to the last region of the source payload, then the fifth source payload, the next source payload, is the first in the next row. Starts in the first area.

Thus, after performing all of the processes described above for the given source payloads, the completed two-dimensional array 212 is the resultant information block.

Meanwhile, packets including a plurality of contents requiring different transmission reliability levels may be included in one source block. In this case, if the amount of repair packets required for one source block is determined based on the packet requiring the highest reliability among the packets included in the one source block, the packets included in the corresponding source block Packets requiring low reliability will be overprotected, rather reducing network efficiency.

On the contrary, when the amount of repair packets required for one source block is determined based on the packet requiring the lowest reliability among the packets included in the one source block, the higher of the packets included in the source block is determined. Packets requiring reliability cannot be recovered.

Accordingly, an embodiment of the present invention to be described later provides a method of dividing a source block into source sub-blocks and efficiently configuring an information block and information sub-blocks to improve decoding performance or increase transmission efficiency. do.

4 is a diagram schematically showing another example of an internal structure of the FEC coding block 102 of the signal transmission apparatus 100 of FIG. 1 according to an embodiment of the present invention.

Referring to FIG. 4, the FEC coding block 102 includes a source block generator 401, a source subblock generator 402, and S information subblock generators, that is, an information subblock generator # 1 (403-1). ), Information subblock generator # 2 (403-2),... Information subblock generator #S (403-S), S parity subblock generators, that is, parity subblock generator # 1 (404-1), parity subblock generator # 2 (404-2),... And a parity subblock generator #S 404 -S, an information block generator 405, a parity block generator 406, an FEC parity packet generator 407, and an FEC source packet generator 408.

When source payloads are input, the source block generator 401 generates a source block 410 including the input source payloads, and converts the generated source block 410 into the source subblock generator 402. And output to the information block generator 405 and the FEC source packet generator 408, respectively.

The source subblock generator 402 inputs a source block output from the source block generator 401, selects source payloads included in the source block, and selects S source subblocks, that is, source subblock #. 1 (411-1), source subblock # 2 (411-2),... Generate each of source subblock #S 411-S, source subblock # 1 411-1, source subblock # 2 411-2,. The source subblock # S 411-S is output to the corresponding information subblock generator. That is, the source subblock generator 402 outputs the source subblock # 1 411-1 to the information subblock generator # 1 403-1, and the source subblock generator # 2 411-2. Is outputted to the information subblock generator # 2 403-2,. The source subblock # S 411-S is outputted to the information subblock generator # S 403-S.

The information subblock generator # 1 403-1, the information subblock generator # 2 403-2,... Each of the information subblock generators #S 403-S inputs a corresponding source subblock output from the source subblock generator 402, and is configured in advance with respect to the input source subblock. An information subblock generation operation corresponding to the subblock is generated to generate the information subblock.

At this time, the information subblock generator # 1 (403-1), the information subblock generator # 2 (403-2),. Each of the information subblock generators #S 403 -S performs the same operation as the operation performed by the information block generator 202 described with reference to FIG. 2.

The information subblock generator # 1 403-1, the information subblock generator # 2 403-2,... Each of the information subblock generators #S 403-S may use a different payload size T and the number m of regions, which will be described in detail below.

First, it is assumed that the payload size T and the number m of regions used in the i-th information subblock generator, that is, the information subblock generator #i (403-i) are T (i) and m (i), respectively. It is assumed that the number of information payloads included in the i th information subblock is K (i).

Next, the S parity subblock generators, that is, parity subblock generator # 1 (404-1), parity subblock generator # 2 (404-2),... Each of the parity subblock generators #S 404-S generates a parity subblock by performing an FEC encoding operation corresponding to an FEC encoding scheme preset in the input information subblock. Here, a codeword generated according to the FEC coding scheme will be referred to as an FEC codeword. It is assumed that the FEC code applied to the i-th parity subblock generator, that is, parity subblock generator #i (404-i), is C (i). Here, the FEC code C (i) may define an association between the K (i) information payloads and the K (i) parity payloads.

Meanwhile, the information block generator 405 inputs a source block output from the source block generator 401 and performs an information block generation operation corresponding to a preset information block generation method for the source block. A block is generated, and the generated information block is output to the parity block generator 406. Here, the information block generation method may exist in various ways, and a detailed description thereof will be omitted.

The parity block generator 406 inputs an information block output from the information block generator 405 and performs a parity block generation operation corresponding to a parity block generation scheme preset for the information block to a parity block. And the generated parity block is output to the FEC parity packet generator 407. Here, the parity block generation method may exist in various ways, and a detailed description of the parity block generation method itself will be omitted.

The FEC parity packet generator 407 includes the parity subblock generator # 1 404-1, the parity subblock generator # 2 404-2, and. S parity subblocks output from each of the parity subblock generators #S 404 -S and a parity block output from the parity block generator 406 are input, and the S parity subblocks and the parity are input. Parity payloads included in the block are used to generate an FEC parity packet. ]

In addition, the FEC source packet generator 408 inputs the source block 410 output from the source block generator 401 and uses the source payloads included in the source block 410 to generate the FEC source packet. Create Here, the FEC source packet generator 408 generates an FEC source packet corresponding to a preset FEC source packet generation method, and a detailed description of the set FEC source packet generation method will be omitted.

4 illustrates another example of an internal structure of the FEC coding block 102 of the signal transmission apparatus 100 of FIG. 1 according to an embodiment of the present invention. Next, the source unit of FIG. 4 will be described with reference to FIG. 5. An example of a process of generating a source subblock of the block generator 402 will be described.

FIG. 5 is a diagram schematically illustrating an example of a process of generating a source subblock of the source subblock generator 402 of FIG. 4.

Referring to FIG. 5, first, the source subblock generator 402 inputs a source block 501 output from the source block generator 401. In FIG. 4, the source block 501 is shown as “410”, and it should be noted that the source block 410 is changed to the reference numeral “501” for convenience of description.

First, the source block 501 includes twelve source payloads, that is, source payload SP0, source payload SP1, and source payload SP11. The source subblock generator 402 divides the 12 source payloads into three source subblocks, namely, source subblock 1 502, source subblock 2 503, and source subblock 3 504. ) Here, the source subblock 1 502 includes four source payloads, that is, source payload SP0, source payload SP1, source payload SP2, and source payload SP3, and the source subblock 2 503 includes four source payloads, source payload SP4, source payload SP5, source payload SP6, and source payload SP7, wherein source subblock 3 504 contains four sources Payloads, namely source payload SP8, source payload SP9, source payload SP10, and source payload SP11 (source subblock 1 502 = {SP0, SP1, SP2, SP3}, source Subblock 2 503 = {SP4, SP5, SP6, SP7}, source subblock 3 504 = {SP8, SP9, SP10, SP11}).

Considering a case where the source subblock generator 402 mathematically expresses the process of generating the source subblocks, the following is described.

First, when the source block SB is divided into S source subblocks SSB (1), SSB (2), ..., SSB (S), the relationship corresponding to the following “source subblock generation rule 1” is established. do.

[Source Subblock Generation Rule 1]

1) The intersection of SSB (i) and SSB (j) is an empty set for integers i and j of all integers between 1 and S.

2) The union of SSB (1), SSB (2), ..., SSB (S) is a subset of SB.

In FIG. 5, an example of a process of generating a source subblock of the source subblock generator 402 of FIG. 4 has been described. Next, a process of generating a source subblock of the source subblock generator 402 of FIG. 4 will be described with reference to FIG. 6. Another example of will be described.

6 is a diagram schematically illustrating another example of a process of generating a source subblock of the source subblock generator 402 of FIG. 4.

Referring to FIG. 6, first, the source subblock generator 402 inputs a source block 601 output from the source block generator 401. In FIG. 4, the source block 601 is shown as “410”, and it should be noted that the source block 410 is changed to the reference numeral “601” for convenience of description.

First, the source block 601 includes 12 source payloads, that is, source payload SP0, source payload SP1, and source payload SP11. The source subblock generator 402 divides the 12 source payloads to generate two source subblocks, namely, source subblock 1 602 and source subblock 2 603. Here, the source subblock 1 602 includes four source payloads, that is, source payload SP0, source payload SP1, source payload SP2, and source payload SP3, and the source subblock 2 603 includes seven source payloads, source payload SP0, source payload SP1, source payload SP2, source payload SP3, source payload SP4, source payload SP5, and source payload. Load SP6 and source payload SP7 (source subblock 1 602 = {SP0, SP1, SP2, SP3}, source subblock 2 603 = {SP0, SP1, SP2, SP3, SP4, SP5) , SP6, SP7}).

Considering a case where the source subblock generator 402 mathematically expresses the process of generating the source subblocks, the following is described.

First, when the source block SB is divided into S source subblocks SSB (1), SSB (2), ..., SSB (S), the relationship corresponding to the following “source subblock generation rule 2” is established. do.

[Source Subblock Generation Rule 2]

1) The intersection of SSB (i) and SSB (i + 1) is SSB (i) for all integers between 1 and S-1.

2) SSB (S) is a subset of SB.

3 and 4 as described above, the information block generator 405 proposed in the present invention inputs a source block 410, and the input source block 410 as described in FIG. Create an information block with a shape. In this case, T, T (1), ..., T (S) of FIG. 4 may have different values.

Meanwhile, another example of the information block generator 405 proposed in the present invention includes S information subblock generators, that is, information subblock generator # 1 403-1, information subblock generator # 2 403-2, … In this case, one information block is generated by concatenating the S information subblocks generated by the information subblock generator #S 403 -S. As described above, when one information block is generated by concatenating the S information subblocks, there is a constraint that T = T (1) = ... = T (S).

The payload size T and the number m of regions used in the information block generator 405 proposed in the embodiments of the present invention are the reliability conditions required by the contents included in the source block input to the information block generator 405. It may be determined by a memory constraint of the FEC decoder, a constraint of the FEC decoding delay time, and the like.

Similarly, T (i) and m (i) used in the i-th information subblock generator also require reliability conditions required by the contents included in the source subblock input to the i-th information subblock generator and the memory of the FEC decoder. Constraints, constraints on the FEC decoding delay time, and the like. In this case, when the contents included in the source subblock are contents requiring high reliability, use of an FEC code having strong error correction code capability is required.

First, the error correction capability of the FEC code is typically improved as the length of the FEC codeword is increased. In the case of converting a given source block or source subblock into an information block, decreasing the value of T increases the number of information payloads included in the information block. As such, when the number of information payloads included in the information block is increased, more powerful FEC codes can be used.

On the other hand, each source subblock is a subset of the source block, and thus contains a smaller amount of data than the source block. Therefore, when T = T (1) = ... = T (S), K (i), i = 1, ..., S, generally have a value smaller than K.

In an embodiment proposed by the present invention, T (i) may be represented by Equation 1 below.

In Equation 1, T ^ a means a power of a.

In another embodiment proposed by the present invention, T (i) may be represented by Equation 2 below.

In FIG. 6, another example of a process of generating a source subblock of the source subblock generator 402 of FIG. 4 has been described. Next, the signal receiving apparatus 110 of FIG. 1 according to an exemplary embodiment of the present invention will be described with reference to FIG. 7. The internal structure of the FEC decoding block 113 will be described.

7 is a diagram schematically illustrating an internal structure of the FEC decoding block 113 of the signal receiving apparatus 110 of FIG. 1 according to an embodiment of the present invention.

Referring to FIG. 7, the FEC decoding block 113 includes a reception source block reconstructor 701, a reception source subblock reconstructor 702, and S received information subblock reconstructors, that is, a reception information subblock. Decompressor # 1 703-1, received information subblock decompressor # 2 703-2,... , Received information subblock reconstructor #S 703-S, S FEC decoders, that is, FEC decoder # 1 704-1, FEC decoder # 2 704-2,... , FEC decoder #S 704-S, a reception information block reconstructor 705, and an FEC decoder 706.

The receiving source block reconstructor 701 analyzes the FEC header included in the FEC source packet received through the signal receiving apparatus 110 to restore the receiving source block 710, and restores the received source block 710. ) Is output to the reception source subblock decompressor 702 and the reception information block decompressor 705.

The receiving source subblock decompressor 702 inputs the receiving source block 710 outputted from the receiving source block decompressor 701, selects source payloads included in the receiving source block 710, and selects S. Receive source subblocks, that is, receive source subblock # 1 711-1, receive source subblock # 2 711-2,. Next, the reception source subblock #S 711 -S is generated, and the generated S reception source subblocks are output to the corresponding reception information subblock reconstructor. That is, the receiving source subblock decompressor 702 outputs the receiving source subblock # 1 711-1 to the receiving information subblock decompressor # 1 703-1, and the receiving source subblock decompressor # 702. 2 (711-2) to the received information subblock decompressor # 2 (703-2),... The reception source subblock #S 711-S is outputted to the reception information subblock decompressor #S 703-S. Here, the information used to detect the reception source block and the reception source subblock including the source payload may be obtained from an FEC header to be described later, and the reception source block and the reception source block including the source payload may be obtained. Since a method of acquiring information used for detecting a block from the FEC header will be described later, a detailed description thereof will be omitted.

On the other hand, the received information subblock decompressor # 1 703-1, the received information subblock decompressor # 2 703-2,... The received information subblock decompressor #i 703-i which is the i th received information subblock decompressor among the received information subblock decompressor #S 703-S is outputted from the received source subblock decompressor 702. Receives by receiving an i-th reception source subblock, i.e., reception source subblock #i, and performing a reception information subblock restoration operation corresponding to a reception information subblock restoration scheme preset for the reception source subblock #i. The recovered sub information #i is restored to the information subblock #i, and the restored sub information #i is output to the corresponding FEC decoder, that is, the FEC decoder #i 704-i. In this case, the reception information subblock reconstructor #i 703-i performs the same operation as the operation performed by the information subblock generator #i 403-i as described with reference to FIG. 4. The payload size and the number of regions required for the operation of the decompressor #i 703-i may be obtained through a separate protocol for transmitting an FEC header or control information, which will be described later. Since a method for acquiring the size of the payload and the number of regions required for the operation (703-i) through the separate protocol for transmitting the FEC header or the control information will be described below, a detailed description thereof will be omitted.

On the other hand, some of the transmission FEC packets transmitted by the signal transmission apparatus 100 may be lost due to the effects of congestion in the network and errors occurring in the physical layer, etc. Transmitted FEC packets are not delivered to the FEC decoding block 113. Accordingly, unlike the signal transmission apparatus 100, the reception source block 710 and the S reception source subblocks, that is, the reception source subblock # 1 711-1 and the reception source subblock # 2 711 -2) and... For the receiving source subblock #S 711 -S, some payload values may not be known. Therefore, a region in which data is not obtained in generating reception information subblocks is typically treated as a loss so that the S FEC decoders, namely FEC decoder # 1 704-1 and FEC decoder # 2 704-2, are treated as loss. ),… Is passed to the FEC decoder #S 704-S.

Therefore, the FEC decoder # 1 704-1, the FEC decoder # 2 704-2,... The FEC decoder #i (704-i), which is the i th FEC decoder of the FEC decoder #S (704-S), is the i th received information subblock, i.e., the i th obtained from the FEC parity packet. The parity payload for the information subblock, i.e., the information subblock #i, i.e., the i th received parity subblock, i.e., the received parity subblock #i, is used to recover the lost transmission FEC packet. In this case, the relation between the parity payload included in the FEC parity packet and the FEC code may be obtained from an FEC header to be described later, and the relation between the parity payload included in the FEC parity packet and the FEC code may be as follows. Since it will be described in detail, detailed description thereof will be omitted here.

Meanwhile, the reception information block reconstructor 706 inputs a reception source block 710 output from the reception source block reconstructor 701, and is a reception information block preset for the reception source block 710. A reception information block restoration operation corresponding to the scheme is performed to restore the reception information block, and the received reception information block is output to the FEC decoder 706.

The FEC decoder 706 restores the lost part using the parity payload, that is, the received parity block, for the received information block output from the received information block reconstructor 706 and the information block obtained from the FEC parity packet. Try and output the restored information block.

In the case of applying the FEC scheme using the partitioning of the source block proposed in an embodiment of the present invention, the signal transmission apparatus 100 may include information indicating which source subblock is included in each source payload, an information block, The number of divided regions included in the information subblock, and information about which region of each information payload starts from which region of the information payload should be transmitted to the signal receiving apparatus 110. If the signal receiving apparatus 110 includes information indicating which source subblock is included in each source payload, the number of divided regions included in the information block and the information subblock, and each source pay block, If the loads do not obtain information on which region of the information payload the FEC decodes, then the FEC decodes because it does not know which FEC source packets were placed in the source block when any FEC source packets were lost. The operation becomes difficult to perform.

Meanwhile, information indicating which source subblock is included in each source payload, and signaling information about the symbol size T and the number m of divided regions are added to each FEC source packet and transmitted or transmitted through a separate packet. Can be sent. Next, a description will be given of a method of transmitting information indicating which source subblock is included in each source payload and signaling information about a symbol size T and the number m of divided regions through separate packets. Same as

First, the apparatus 100 for transmitting a signal includes a content delivery protocol such as a session description protocol (SDP), hereinafter referred to as "SDP" (hereinafter referred to as CDP). Information indicating the relationship between the source block and the source subblock and T, T (1), ..., T (S) and m, m (1), ..., m ( S) together with the signal receiving apparatus 110, or information indicating the relationship between the source block and the source subblock, and T, T (1), ..., T (S) and m, m (1 ), ..., m (S) may be transmitted to the signal receiving device 110. Here, when T is not a multiple of m, a predetermined appointment between the signal transmission device 100 and the signal reception device 110 (for example, the upper region includes [T / m] +1 columns and the lower region) [T / m] to include the columns), the signal receiving apparatus 110 may detect the number of columns included in each region by using the values of T and m.

In the above description, information indicating which source subblock is included in each source payload and signaling information about a symbol size T and the number m of divided regions are added to each FEC source packet and transmitted or a separate packet is transmitted. The case of transmission through the above has been described.

On the other hand, the signal transmission apparatus 100 must transmit separate information so that the signal receiving apparatus 110 can determine the form in which the source payload is arranged in the information block and the information subblock. First, in order to determine a form in which a source payload received by the signal receiving apparatus 110 is disposed in an information block and an information subblock, the signal transmitting apparatus 100 may determine each source payload. Information indicating the position of the row where the arrangement starts, that is, the order of the FEC coded symbols and the location of the region starting within the corresponding FEC coded symbol may be added to each FEC source packet and transmitted to the signal receiving apparatus 110.

Table 1 below shows an example of signaling information added to an FEC source packet according to an embodiment of the present invention.

.... Source Block Number (SBN) Payload Type If (Payload type == Source Payload) {
Encoding Symbol ID (ESI)
Payload Start Position (PSP)
Number of associated Source Sub-Blocks (N)
For i = 1 to N {
Source Sub-Block Number (SSBN (i))
Encoding Symbol ID for SSBN (i) (ESI (i))
Packet Start Position for SSBN (i) (PSP (i))
}
} If (Payload type == Parity Payload for Source Block) {
Encoding Symbol ID (ESI)
Information Block Length (IBL)
T, m
} If (Payload type == Parity Payload for Source Sub-Block) {
Source Sub-Block Number (SSBN)
Encoding Symbol ID (ESI)
Information Sub-Block Length (ISBL)
T (SSBN), m (SSBN)
}

Referring to Table 1, signaling information added to the FEC source packet includes a source block number (SBN) and a payload type.

The source block number SBN indicates a source block corresponding to the corresponding FEC packet. In addition, the payload type indicates what type of data the payload included in the FEC packet includes, that is, the type of payload included in the FEC packet. Here, the payload type may be classified into three types, namely, a source payload, a parity payload associated with a source block, and a parity payload associated with a source subblock.

Meanwhile, in Table 1, the signaling information added to the FEC source packet may include additional information corresponding to the payload type, which will be described below.

First, when the payload type indicates a source payload (Payload type == Source Payload), signaling information added to the FEC source packet includes an encoding symbol identifier (ESI) and a payload start position. (Payload Start Position: PSP), the number of associated source sub-blocks (N), the source subblock number from 1 to N for the number N of the associated source subblocks, and The apparatus further includes a coded symbol identifier for a source subblock number and a packet start position for the corresponding source subblock number. In Table 1, the source subblock number for the i-th source subblock is represented by a Source Sub-Block Number (SSBN (i)), and the encoding symbol identifier for the i-th source subblock is Encoding Symbol ID for It is represented by SSBN (i) (ESI (i)), and the packet start position for the i-th source subblock is represented by Packet Start Position for SSBN (i) (PSP (i)).

Second, when the payload type indicates a parity payload for a source block (Payload type == Parity Payload for Source Block), the signaling information added to the FEC source packet may include an encoding symbol identifier (ESI) and information. It further includes an Information Block Length (IBL), hereinafter referred to as “IBL”, and T and m.

Third, when the payload type indicates a parity payload for a source subblock (Payload type == Parity Payload for Source Sub-Block), the signaling information added to the FEC source packet is a source subblock length (SSBN). ), A coded symbol identifier (ESI), an information sub-block length (ISBL, hereinafter referred to as "ISBL"), T (SSBN), and m (SSBN).

Meanwhile, the payload type will be described with reference to FIG. 1.

First, referring to FIG. 1, in another embodiment of the present invention, the payload type is transmitted to the protocol B processing block 103 in the form of control information, and in the protocol B processing block 103, the payload type is a protocol. It is included in the header of B. In this case, the payload type may be omitted from the signaling information added to the FEC source packet as described in Table 1.

When the payload type of the corresponding FEC packet indicates the source payload, the encoding symbol identifier (ESI), hereinafter referred to as "ESI", is the first coded symbol at which the FEC source packet starts, that is, an information block. The position of a row in the frame is indicated, and a payload start position (Payload Start Position: PSP, hereinafter referred to as "PSP") indicates a region in which the source payload starts in the information block. For example, assuming that m = 4 in FIG. 3, the pair of the ESI value and the PSP value of the first FEC source packet is (0, 0), and the ESI value and PSP of the second FEC source packet. The pair of values is (1, 2), and the pair of ESI and PSP values of the third FEC source packet is (3, 3), and the pair of ESI and PSP values of the fourth FEC source packet is (6). , 1).

In addition, the number N of the source subblocks indicates the number of source subblocks including the corresponding FEC source packet. SSBN (i), which is a source sub-block number (SSBN, hereinafter referred to as “SSBN”) for integers 1 to N, indicates a source subblock to which the corresponding FEC source packet corresponds. , ESI (i) indicates the first coded symbol where the FEC source packet starts in the corresponding information subblock, that is, the position of a row in the information subblock, and PSP (i) indicates that the source payload is placed in the information subblock. Indicates the started area. In another embodiment of the present invention, when the number N of the source subblocks is a constant, the number N of the source subblocks is not repeatedly transmitted for every FEC packet, and a system initialization process or service acquisition process of a broadcasting and communication system is performed. The number N of the source subblocks may be omitted from Table 1, as included in the control signal transmitted from.

In addition, when the payload type of the corresponding FEC packet indicates a parity payload associated with the source block, the number N of the source subblocks is always 1 and the PSP is always 0 and thus may be omitted.

On the other hand, assuming that the number of information payloads included in the information block is K, the coded symbol identifier (ESI) of the FEC source packet is typically 0, 1, 2, ..., in order for each source symbol. Although assigned with a value of (K-1), the coded symbol identifier (ESI) of the FEC parity packet may be assigned according to the system requirements of the broadcasting and communication system. For example, the coded symbol identifier (ESI) of the FEC parity packet may be sequentially assigned to each repair symbol like 0, 1, 2, ... like the coded symbol identifier (ESI) of the FEC source packet. have. In this case, there is an advantage that the octet size required for the encoded symbol identifier (ESI) of the repair packet can be minimized.

Meanwhile, in another embodiment of the present invention, the recovery symbol is regarded as a coded symbol concatenated after the source symbol, and the ESI for each parity symbol is equal to K, (K + 1), (K + 2), ... It may be assigned in order.

In addition, as another embodiment of the present invention, when the source block is divided into m regions and each source symbol is regarded as m subdivided symbols, a total of m * K subdivided symbols are included in one source block. It exists. Thus, for each repair symbol, the coded symbol identifier (ESI) for the FEC parity packet can be assigned sequentially, such as m * K, (m * K + 1), (m * K + 2), ... have.

In addition, the signal transmission apparatus 100 will be referred to as a source block length SBL, which indicates the total number of rows of regions included in the source block to the signal reception apparatus 110. ) And T, m to indicate the exact structure of the source block, and thus the signal receiving apparatus 110 can detect the exact structure of the source block transmitted by the signal transmitting apparatus 100.

If the payload type of the corresponding FEC packet indicates a parity payload related to the source subblock, an identifier for the source subblock, that is, a source subsubblock number (SSBN) is added and subsequent information is added to the information subblock. Except for the information, the payload type is the same as the case of representing the parity payload associated with the source block.

It is apparent that the FEC header as shown in Table 1 includes only the minimum information necessary to carry out the embodiments of the present invention, and may include additional information according to the system requirements of the broadcasting and communication system. Do.

In addition, in the embodiment of the present invention, even if there is a separate means having high reliability for transmitting control information, only a part of N, T, m, IBL, and ISBL among the fields included in the FEC header may transmit the control information. The FEC source packet header may be transmitted using a separate means having high reliability. The FEC source packet header may be transmitted to a source block identifier (SBN) and a source subblock identifier (SSBN), and a coded symbol identifier (ESI) and a source subblock for the corresponding source block. The coded symbol identifier (ESI) must be included. In addition, the FEC parity packet header must include a source block identifier (SBN) and a coded symbol identifier (ESI). When the payload type of the FEC parity packet refers to a parity payload related to a source subblock, a source subblock identifier (SSBN) must be included in the FEC packet header.

In the present invention, since the source payload is protected by one or more FEC codes, the signal reception apparatus may dynamically update the reception source block in the FEC decoding process to obtain a decoding performance improvement.

Meanwhile, an operation process of the FEC decoding block 113 of the signal receiving apparatus 110 of FIG. 1 according to an embodiment of the present invention will be described with reference to FIG. 7 again as follows.

Referring to FIG. 7, in an embodiment of the present invention, the receiving source block reconstructor 701 first generates only the first receiving source subblock, and the first receiving source subblock uses FEC code C (1). That is, FEC is decoded via the FEC decoder # 1 704-1, and thus restoration of the lost source payload is attempted. If there is a recovered source payload, the receiving source block decompressor 701 updates the receiving source block and restores a second receiving source subblock using the updated receiving source block. In this way, the same process as for the first receiving source subblock until the Sth receiving source subblock, which is the last receiving source subblock, that is, the FEC code C (S) for the Sth receiving source subblock. Is used, i.e., FEC is decoded via the FEC decoder #S 704-S, and therefore restoration of the lost source payload is attempted.

Then, the reception information block reconstructor 705 restores the reception information block using the updated reception source block using the result of decoding all the information subblocks last, and using the FEC code C, i.e., FEC The decoder 706 attempts to recover the lost source payload.

On the other hand, unlike the above description, as another embodiment of the present invention, after the signal receiving apparatus 110 independently decodes each source subblock, the result of decoding all information subblocks It is also possible to update the receiving source block once using the same, to construct an information block using the updated receiving source block again, and to try to recover the lost source payload using the FEC code C.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by those equivalent to the scope of the claims.

Claims (12)

In a method for transmitting a packet by a transmitting device in a broadcasting system,
Identifying a source block including a plurality of source data units;
Generating a plurality of source sub-blocks using the source block, each source sub-block including one or more source data units of the plurality of source data units;
Generating a plurality of information subblocks using the plurality of source subblocks, each information subblock including one or more information data units;
A plurality of parity subblocks are generated by performing Forward Error Correction (FEC) encoding on the plurality of information subblocks, and parity is performed by performing FEC encoding on information blocks including the plurality of information subblocks. Generating a block;
Generating at least one FEC parity packet based on the plurality of parity subblocks and the parity block;
Transmitting the at least one FEC parity packet, wherein a first FEC parity packet of the at least one FEC parity packet includes information used to identify a repair symbol in the first FEC parity packet. Transmission method. The method of claim 1,
A first information data unit of the one or more information data units includes information indicating a length of a source data unit associated with the first information data unit. The method of claim 1,
And wherein the first FEC parity packet includes information about an information block associated with the first FEC parity packet. In a method for receiving a packet in a broadcast system,
Receiving at least one forward error correction (FEC) parity packet; And
Performing FEC decoding based on the at least one FEC parity packet,
The at least one FEC parity packet is a parity block generated by performing FEC encoding on a plurality of parity subblocks generated by performing FEC encoding on a plurality of information subblocks and an information block including the plurality of information subblocks. Is generated based on
The plurality of information subblocks are generated using a plurality of source subblocks, each information subblock comprising one or more information data units;
The plurality of source subblocks are generated using a source block comprising a plurality of source data units, each source subblock including one or more source data units of the plurality of source data units;
And a first FEC parity packet of the at least one FEC parity packet includes information used to identify a repair symbol in the first FEC parity packet. The method of claim 4, wherein
A first information data unit of the one or more information data units includes information indicating a length of a source data unit associated with the first information data unit. The method of claim 4, wherein
And wherein the first FEC parity packet includes information about an information block associated with the first FEC parity packet. In the transmission apparatus in a broadcasting system,
Identify a source block comprising a plurality of source data units,
Generate a plurality of source sub-blocks using the source block, each source sub-block including one or more source data units of the plurality of source data units;
Generate a plurality of information subblocks using the plurality of source subblocks, each information subblock including one or more information data units;
A plurality of parity subblocks are generated by performing Forward Error Correction (FEC) encoding on the plurality of information subblocks, and parity is performed by performing FEC encoding on information blocks including the plurality of information subblocks. Create a block,
At least one processor for generating at least one FEC parity packet based on the plurality of parity subblocks and the parity block; And
A transmitter for transmitting the at least one FEC parity packet,
And a first FEC parity packet of the at least one FEC parity packet includes information used to identify a repair symbol in the first FEC parity packet. The method of claim 7, wherein
And a first information data unit of the one or more information data units includes information indicating a length of a source data unit associated with the first information data unit. The method of claim 7, wherein
And the first FEC parity packet includes information about an information block associated with the first FEC parity packet. In the reception apparatus in a broadcasting system,
A receiver for receiving at least one Forward Error Correction (FEC) parity packet; And
At least one processor that performs FEC decoding based on the at least one FEC parity packet,
The at least one FEC parity packet is generated by performing FEC encoding on an information block comprising a plurality of parity subblocks and the plurality of information subblocks generated by performing forward error correction encoding on a plurality of information subblocks. Generated based on the parity block,
The plurality of information subblocks are generated using a plurality of source subblocks, each information subblock comprising one or more information data units;
The plurality of source subblocks are generated using a source block comprising a plurality of source data units, each source subblock including one or more source data units of the plurality of source data units;
And a first FEC parity packet of the at least one FEC parity packet includes information used to identify a repair symbol in the first FEC parity packet. The method of claim 10,
And a first information data unit of the one or more information data units includes information indicating a length of a source data unit associated with the first information data unit. The method of claim 10,
And the first FEC parity packet includes information about an information block associated with the first FEC parity packet.

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