WO2008037721A2 - Procédé et dispositif de reconstruction d'au moins un paquet de données - Google Patents

Procédé et dispositif de reconstruction d'au moins un paquet de données Download PDF

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Publication number
WO2008037721A2
WO2008037721A2 PCT/EP2007/060175 EP2007060175W WO2008037721A2 WO 2008037721 A2 WO2008037721 A2 WO 2008037721A2 EP 2007060175 W EP2007060175 W EP 2007060175W WO 2008037721 A2 WO2008037721 A2 WO 2008037721A2
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WO
WIPO (PCT)
Prior art keywords
packet
packets
code
dimensional block
faulty
Prior art date
Application number
PCT/EP2007/060175
Other languages
German (de)
English (en)
Other versions
WO2008037721A3 (fr
Inventor
Jürgen PANDEL
Rainer Stademann
Original Assignee
Nokia Siemens Networks Gmbh & Co. Kg
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by Nokia Siemens Networks Gmbh & Co. Kg filed Critical Nokia Siemens Networks Gmbh & Co. Kg
Publication of WO2008037721A2 publication Critical patent/WO2008037721A2/fr
Publication of WO2008037721A3 publication Critical patent/WO2008037721A3/fr

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Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M13/00—Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes
    • H03M13/29—Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes combining two or more codes or code structures, e.g. product codes, generalised product codes, concatenated codes, inner and outer codes
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M13/00—Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes
    • H03M13/29—Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes combining two or more codes or code structures, e.g. product codes, generalised product codes, concatenated codes, inner and outer codes
    • H03M13/2906—Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes combining two or more codes or code structures, e.g. product codes, generalised product codes, concatenated codes, inner and outer codes using block codes
    • H03M13/2909—Product codes
    • H03M13/2915—Product codes with an error detection code in one dimension
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M13/00—Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes
    • H03M13/29—Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes combining two or more codes or code structures, e.g. product codes, generalised product codes, concatenated codes, inner and outer codes
    • H03M13/2906—Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes combining two or more codes or code structures, e.g. product codes, generalised product codes, concatenated codes, inner and outer codes using block codes
    • H03M13/2927—Decoding strategies
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M13/00—Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes
    • H03M13/37—Decoding methods or techniques, not specific to the particular type of coding provided for in groups H03M13/03 - H03M13/35
    • H03M13/373—Decoding methods or techniques, not specific to the particular type of coding provided for in groups H03M13/03 - H03M13/35 with erasure correction and erasure determination, e.g. for packet loss recovery or setting of erasures for the decoding of Reed-Solomon codes

Definitions

  • the invention relates to a method and a device for reconstructing at least one data packet.
  • DVB Digital Video Broadcast
  • the digital television signals to be transmitted are transmitted in data packets using the IP (Internet Protocol) standard from one transmitter to one or a plurality of receivers.
  • IP Internet Protocol
  • transmission takes place via DSL (DSL - Digital Subscriber Line).
  • DSL DSL - Digital Subscriber Line
  • transmission errors can occur, with erroneous data packets being discarded, for example.
  • causes of transmission errors include congestion of routers in the network, interference on broadband access lines, or transmission errors in wireless home networks, such as WLAN (WLAN - Wireless Local Area Network).
  • Loss of data packets represented by compressed multimedia data in digital television signals may be e.g. due to error propagation during decoding, lead to massive quality losses.
  • payment services such as Video on Demand, is to ensure the most error-free reconstruction in the receiver even with transmission errors.
  • a large number of methods for error protection and reconstruction of erroneous data are known, with the aid of the data packets to be protected additional redundant data packets (redundancy packets) being generated that are erroneously detected at the receiver for error detection and / or reconstruction.
  • catching data packets can be used.
  • the coding and the decoding take place in blocks, for example, whereby a reconstruction property of data packets can be improved, the more data packets are taken into account in a data block, which is taken into account in the coding or decoding.
  • the invention is thus based on the object of specifying an apparatus and a method with which both the reconstruction property is improved by using large data blocks and also a storage efficiency for the reconstruction of the data blocks.
  • the invention relates to a method for reconstructing at least one data packet of a two-dimensional block code, wherein in each x-th row of the two-dimensional block code the associated data packets and at least a first redundancy packet with a systematic code and each y-th column of the two -dimensional block codes the associated data packets and at least a second redundancy packet are encoded with a parity code, wherein for several lines of the two-dimensional block code (al) decodes the data packets of the xth line with systematic codes in intermediate packets (a2) at least one end packet is generated by applying the encoding rule of the parity code to at least one of the error-free intermediate packets and at least one of the end packets, and wherein these intermediate packets are faulty or error-free after performing these steps for the rows at least for one of the columns of the two-dimensional block code (bl) a number of faulty intermediate pacts per column is determined based on at least one of the stored positions (POS), and (b2) the faulty
  • the erroneous intermediate packets are corrected by using the parity code, ie an encoding rule of the parity code and the associated second redundancy packets, and using the at least one end packet.
  • the use of a large number of data packets can significantly reduce an unreconstructible residual error in transmitted data packets.
  • at least one faulty intermediate packet is pre-assigned before the execution of step a by a predefinable value, in particular a binary value 0.
  • a predefinable value in particular a binary value 0.
  • faulty intermediate packages can also be preset with binary values or other values other than 0, as long as the predefinable value ensures that no change in a content of the final value takes place when this value is linked to the final value.
  • a binary zero with one of the end packets exactly generates the content of the end packet again.
  • step a3 Is preferably before the first execution of step a3 one or more end packages to a predetermined additional
  • the pre-assignment with the predeterminable further value therefore ensures that there is no need to query whether the creation of the end values is performed for the first time, as a result of which an acceleration of the procedure for correcting the faulty intermediate packets, i. H. for the reconstruction of at least one of the data packets is realized.
  • the position of the at least one faulty intermediate packet is deleted, the faulty intermediate packet, the cor- was rectified, replaced by the corresponding error-free intermediate package and then the steps of the procedure are re-executed.
  • a renewed execution of the steps of the method according to the invention a further reduction of defective intermediate packets or an increase in reconstructed data packets is made possible.
  • the erroneous intermediate packets reconstructed during the first pass are used by this iterative repetition of the steps in order to be able to correct further erroneous intermediate packets.
  • the steps are preferably repeated until no faulty intermediate packets can be corrected, or until all faulty intermediate packets have been reconstructed.
  • the iterative development of the invention can then be terminated if no further improvement is achieved in an iteration step. This avoids unnecessary iterative repetitions of the steps and thus accelerates the reconstruction.
  • the invention also relates to an apparatus for reconstructing at least one data packet of a two-dimensional block code, wherein in each x-th row of the two-dimensional block code the associated data packets and at least a first redundancy packet with a systematic code and in each y-th column of the second dimensional block codes the associated data packets are encoded with a parity code
  • the device comprising the following means: a first decoding means for decoding the data packets of the x-th row by means of the systematic code in intermediate packets, these intermediate packets being erroneous or error-free; a first storage means for storing a position of a respective defective intermediate packet; accumulator means for generating at least one end packet by applying the encoding law of the parity code to at least one error-free intermediate packet and to at least one of the end packets; a second decoding means for determining in each case a number of error-free intermediate packets per column based on at least the position stored in the first memory means, and for correcting the er
  • Figure 1 shows a structure of a two-dimensional block code
  • FIG. 2 shows a flow chart for carrying out a method for decoding a data packet
  • FIG. 3 shows a device for carrying out the method for decoding the data packet
  • Figure 4A-4D positions of erroneous data packets in iterative passage of the method.
  • FIGS. 1 to 4 Elements with the same function and mode of operation are provided in FIGS. 1 to 4 with the same reference numerals.
  • a data packet comprises one or more symbols of a predefinable length.
  • each data packet D (x, y) comprises exactly one symbol of length 1 bit, wherein a position of the data packet in a two-dimensional block code ZDB is denoted by a reference symbol x for one row and a reference character y for a column of the two -dimensional block codes ZDB.
  • first redundancy packets R (I, 1),..., R (5,3) are formed in each case.
  • These first redundancy packets are generated using a systematic code SC, such as a Rapter code or a Low Density Parity Check code.
  • SC systematic code
  • a Rapter code or a Low Density Parity Check code.
  • S (I),..., (S15) is generated for the data packets per column.
  • a parity code PC is used.
  • the second redundancy symbols S are thus generated as follows:
  • the transmitter ie the video-on-demand server, next transmits the data packets D1 (1,1), ..., D (5, 15), the first and second redundancy packets R (I, 1), ... , R (5,3), S (I), ..., S (15) to the receiver.
  • the order of the packets in the concrete transmission is irrelevant to the invention.
  • the receiver By interfering with the transmission, one or more of the packets, e.g. the data packets D (3, 15), the receiver is faulty. If a packet is lost during transmission, this packet is marked as faulty.
  • the flowchart according to FIG. 2, which enables a reconstruction of faulty data packets, is started in state STA. Here are the steps:
  • Step S3 The erroneous intermediate packets from the second step S2 are detected and their position POS (x, y) is temporarily stored within the two-dimensional block code with the coordinates (x, y) in a first memory module SMl. It follows a step S4.
  • Step S4 In this step, the error-free intermediate packet Z2 with the corresponding end packages by applying the encoding rule of the parity code PC, so that the final packets E (I), ..., E (15) are generated.
  • the final packet E (I) is formed by the following rule:
  • Step S5 In this step, it is checked whether steps S2 to S4 have been performed for all the lines. If this is not the case, i ⁇ N, then proceed to step S6. Otherwise, S7 is executed as the next step.
  • Step S8 In step S8, a number A of defective intermediate packets per column i is determined for the column i of the two-dimensional block code. This determination is made by analyzing the stored positions POS (x, y). Subsequently, a step S9 is performed.
  • step S4 only the error-free intermediate packets were taken into account in step S4 for the creation of the end-of-packet.
  • all intermediate packages for the preparation of the final packages can be taken into account, if the faulty intermediate packages, eg Zl (5, 15), are pre-assigned by a predeterminable value W before the final packages are created, the value W being used to generate one of the final values faulty intermediate packet causes no change in the final value before generation.
  • these can be further processed in the set-top box of the recipient. For example, they are decoded by an MPEG2 (MPEG - Motion Picture Expert Group) decoder and the decoded image is visually displayed on a user's monitor.
  • MPEG2 MPEG - Motion Picture Expert Group
  • FIG. 3 shows a device DV for carrying out the method for reconstructing a data packet.
  • the two-dimensional block code ZDB is first transferred to a first decoding module DM1.
  • the first decoding module performs the steps S1 to S6 according to the flowchart of FIG.
  • the position POS (x, y) of the respective defective intermediate packet is stored in the first memory module SMl organized.
  • At least the faulty intermediate packets Z2 (1, 1),..., Z (N, M) are stored in the second memory module SM2.
  • An accumulator module AM performs the generation of the end packets E (I), ..., E (M) according to step S4 of FIG. 2 after decoding each line of the two-dimensional block code.
  • the final packets are buffered in the accumulator module.
  • a second decoding module DM2 the steps S7 to S12 of the flowchart of FIG. 2 are performed.
  • the second redundancy packets S (I),..., S (M) are supplied by the first decoding module DM1, the positions of faulty intermediate packets from the first memory module SM1 and the respective end packets from the accumulator module to the second decoding module DM2.
  • This determines the number of defective intermediate packages in columns and, if the number is equal to one, corrects the faulty intermediate package.
  • the corrected, ie error-free, intermediate package becomes to the second memory module for overwriting the faulty intermediate packet at the same position x, y.
  • the device DV can be implemented and implemented in hardware, software or in a combination of hardware or software. Furthermore, it can be integrated in a portable terminal, for example a GSM (Global System for Mobile Communications) mobile telephone or a stationary terminal, for example a set-top box.
  • GSM Global System for Mobile Communications
  • faulty intermediate packets Z1 (x, y) are marked with a symbol "X" and error-free intermediate packets Z2 (x, y) and D (x, y) are marked with a symbol "_”.
  • faulty intermediate packets are first corrected according to the explanations relating to FIG. 2, the systematic code and the parity code, ie parity code, being designed such that a faulty intermediate packet can only be corrected if it is in a line or column only faulty intermediate package is. Thus, a correction is performed line by line and then column by column. The final Result can be seen in Figure 4B.
  • data packets may have one or more bits.
  • each row of the two-dimensional block code may comprise a different number of data packets, taking into account only those data packets for forming the second redundancy packet (s) located in a column of the two-dimensional block code.
  • the first and the second redundancy packets may each have different numbers per row or per column, for example in the second column three and in the fourth column five second redundancy packets.
  • one or more end packets per column of the two-dimensional block code may generally be used.

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  • Physics & Mathematics (AREA)
  • Probability & Statistics with Applications (AREA)
  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Data Exchanges In Wide-Area Networks (AREA)
  • Error Detection And Correction (AREA)
  • Detection And Prevention Of Errors In Transmission (AREA)

Abstract

Procédé de reconstruction d'au moins un paquet de données d'un code de bloc bidimensionnel. Dans chaque x-ème ligne du code de bloc, les paquets de données correspondants et au moins un premier paquet de redondance sont codés avec un code systématique, et dans chaque y-ème colonne du code de bloc, les paquets de données correspondants et au moins un premier paquet de redondance sont codés avec un code de parité. Pour plusieurs lignes, (a1) les paquets de données de la x-ème ligne sont décodés avec des codes systématiques en paquets intermédiaires contenant des erreurs ou non; (a2) une position respective d'un paquet intermédiaire contenant des erreurs est enregistrée; (a3) au moins un paquet terminal est produit par utilisation de la consigne de codage du code de parité sur au moins un des paquets intermédiaires contenant des erreurs et sur au moins un des paquets terminaux; après réalisation de ces étapes pour les lignes, pour au moins une colonne du code de bloc (b1) un nombre respectif de paquets intermédiaires contenant des erreurs est déterminé par colonne sur la base d'au moins une des positions enregistrées (POS); et (b2), le paquet intermédiaire contenant des erreurs est corrigé en paquet de données au moyen du code de parité, à l'aide du ou des paquets terminaux, si le nombre est égal à 1. L'invention concerne également un dispositif de mise en oeuvre de ce procédé.
PCT/EP2007/060175 2006-09-26 2007-09-25 Procédé et dispositif de reconstruction d'au moins un paquet de données WO2008037721A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE200610045311 DE102006045311A1 (de) 2006-09-26 2006-09-26 Verfahren und Vorrichtung zum Rekonstruieren zumindest eines Datenpaketes
DE102006045311.5 2006-09-26

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WO2008037721A2 true WO2008037721A2 (fr) 2008-04-03
WO2008037721A3 WO2008037721A3 (fr) 2008-05-22

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020049947A1 (en) * 2000-06-02 2002-04-25 Satish Sridharan Product code based forward error correction system
US6658620B1 (en) * 2000-01-11 2003-12-02 Northrop Grumman Corporation Burst and packet wireless transmission using product codes with iterative decoding
WO2005006563A1 (fr) * 2003-07-09 2005-01-20 Thomson Licensing Procede de correction d'erreur pour codes de produits reed-solomon

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6697996B2 (en) * 2001-05-18 2004-02-24 Lockheed Martin Corp. Multi-dimensional packet recovery system and method
ATE490603T1 (de) * 2004-02-13 2010-12-15 Alcatel Lucent Iterative dekodierung zweidimensionaler blockkodes

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6658620B1 (en) * 2000-01-11 2003-12-02 Northrop Grumman Corporation Burst and packet wireless transmission using product codes with iterative decoding
US20020049947A1 (en) * 2000-06-02 2002-04-25 Satish Sridharan Product code based forward error correction system
WO2005006563A1 (fr) * 2003-07-09 2005-01-20 Thomson Licensing Procede de correction d'erreur pour codes de produits reed-solomon

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
TIEN-YUAN HSIAO ET AL: "An AS-DSP for forward error correction applications" SIGNAL PROCESSING SYSTEMS DESIGN AND IMPLEMENTATION, 2005. IEEE WORKSHOP ON ATHENS, GREECE NOVEMBER 2 - 4, 2005, PISCATAWAY, NJ, USA,IEEE, 2. November 2005 (2005-11-02), Seiten 609-612, XP010882641 ISBN: 0-7803-9333-3 *

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DE102006045311A1 (de) 2008-03-27
WO2008037721A3 (fr) 2008-05-22

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