Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/004—Arrangements for detecting or preventing errors in the information received by using forward error control
  • H04L1/0056—Systems characterized by the type of code used
  • H04L1/0071—Use of interleaving
• • 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
  • H03M13/27—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 using interleaving techniques
  • H03M13/2703—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 using interleaving techniques the interleaver involving at least two directions
• • 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
  • H03M13/27—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 using interleaving techniques
  • H03M13/2703—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 using interleaving techniques the interleaver involving at least two directions
  • H03M13/2707—Simple row-column interleaver, i.e. pure block interleaving
• • 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
  • H03M13/27—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 using interleaving techniques
  • H03M13/2703—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 using interleaving techniques the interleaver involving at least two directions
  • H03M13/2717—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 using interleaving techniques the interleaver involving at least two directions the interleaver involves 3 or more directions
• • 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
• • 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
  • H03M13/2912—Product codes omitting parity on parity
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/004—Arrangements for detecting or preventing errors in the information received by using forward error control
  • H04L1/0041—Arrangements at the transmitter end
• • 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
  • H03M13/03—Error detection or forward error correction by redundancy in data representation, i.e. code words containing more digits than the source words
  • H03M13/05—Error detection or forward error correction by redundancy in data representation, i.e. code words containing more digits than the source words using block codes, i.e. a predetermined number of check bits joined to a predetermined number of information bits
  • H03M13/13—Linear codes
  • H03M13/15—Cyclic codes, i.e. cyclic shifts of codewords produce other codewords, e.g. codes defined by a generator polynomial, Bose-Chaudhuri-Hocquenghem [BCH] codes
  • H03M13/151—Cyclic codes, i.e. cyclic shifts of codewords produce other codewords, e.g. codes defined by a generator polynomial, Bose-Chaudhuri-Hocquenghem [BCH] codes using error location or error correction polynomials
  • H03M13/1515—Reed-Solomon codes

Definitions

• the invention relates to the transmission of data by wave transmission infrastructures.
• wave transmission infrastructure is meant here any communication infrastructure in which the data transmission takes place by means of waves. Therefore, it may be both a radio communication network and a broadcast network. As non-limiting examples, it may therefore be a wireless broadcast network (for example a terrestrial network of DVB-H type (for "Digital Video Broadcasting - Handhelds” - mobile TV), or a hybrid network (that is to say both satellite and terrestrial (for example a DVB-SH type network (for "Digital Video Broadcasting - Satellite Services to Handhelds") (or DVB-SSP) - coupled satellite channel to a terrestrial radio relay channel)), or a cellular or mobile network (such as for example a GSM / EDGE or UMTS type network) or even a metropolitan network or MAN (for "Metropolitan Area Network).
• a wireless broadcast network for example a terrestrial network of DVB-H type (for "Digital Video Broadcasting - Handhelds" - mobile TV)
• a hybrid network that is to say both satellite and terrestrial (for example a
• the DVB-SH network is a hybrid variant of the DVB-H network (for "Digital Video Broadcasting - Handhelds") which has been developed for mobile television, ie for the one-way broadcasting of content. , such as television programs, in broadcast mode (broadcast / point-to-point) or in multicast mode (point-to-multipoint).
• the satellite channel is intended to provide global coverage while the terrestrial relay radio channel is intended to provide the ground with a cellular type coverage.
• the transmission of content in broadcast mode or in multicast mode is done through dedicated services, which may possibly be time multiplexed.
• the radio signals transmitted by an infrastructure are subject to degradation, in particular when they borrow the band S (between about 1. 55 GHz and about 5.2 GHz).
• the level of these impairments may vary depending on the environment of the communication terminals which are the recipients of the transmitted data (possibly content).
• the propagation channel can be in different states depending on the level of weakening of the direct signal induced by a local shadow zone (for example because of the presence of tree (s) or building (s). )).
• LOS for Line Of Sight
• the Markov model reproduces large or very small signal attenuation variations in two main environments called “intermediate shading by trees” (or ITS for Intermediate Tree Shadowing ”) and suburban (or SUB for" suburban ").
• certain networks implement a large-scale temporal diversity.
• the latter can be provided by interleaving (or “interleaving") performed at the level of the physical layer (for class 2 terminals) or the link layer (for class 1 terminals).
• Interleaving at the link layer is an IP interleaving called MPE-IFEC (for "MulitiProtocol Encapsulation - Inter-bursts Forward Error Code” - "Multiprotocol Encapsulation - Forward Error Encoding”) ).
• the MPE-IFEC technique is based on the paralleling of the first M (encoding / decoding) matrices, called ADTs (for "Application Data Tables"), and made up of subsets of data of at least one burst (possibly IP (Internet Protocol)) received, the subsets of data of each burst being distributed in at least one encoding / decoding matrix, then the paralleling of M second matrices, called FDT (for "FEC Data Tables”) and consist of parity symbols resulting from an encoding (Reed-Solomon type) of the data contained in the first M matrices, and finally the distribution by simple interleaving subsets of parity symbols of each second matrix in S successive sets containing at least the respective data of successive bursts received.
• ADTs Application Data Tables
• the S FEC data sets are sent with the associated data in a time slice generally called burst time slice (or "time-slice burst”).
• burst time slice or "time-slice burst”
• the MPE-IFEC coding technique is also described in DVB Bluebook A.131, entitled “MPE-IFEC (draft TS 102 772 V1.1.1)", published in November 2008 by the ETSI (European Telecommunications Standard Institute). .
• An ITS environment imposes an increase in the length of consecutive erroneous bursts, and a reduction in the length of consecutive non-errored bursts is reduced.
• a SUB environment imposes a reduction in the length of the consecutive erroneous bursts, and an increase in the length of the consecutive non-erroneous bursts.
• the MPE-IFEC technique is truly efficient in the presence of an ITS environment only if the depth of the interleaving is important (typically 30 seconds, which corresponds to a variable S of value high), while it is truly efficient in the presence of a SUB environment only if the depth of the interleaving is low (typically 10 seconds, which corresponds to a variable S of low value).
• the operator of a network type DVB-SH is therefore forced to configure the latter according to the worst environment, namely the ITS environment.
• the invention therefore aims to improve the situation in a wave transmission infrastructure.
• the method according to the invention may comprise other characteristics that can be taken separately or in combination, and in particular:
• variable B can be equal to 3;
• the first M matrices can be constituted using a technique called “multiprotocol encapsulation (MPE)";
• the M second matrices and the third M matrices can be constituted by means of a technique called "direct error correction"
• the invention also proposes a codec (or "codec-decoder") intended to equip communication equipment adapted to connect to a transmission infrastructure by means of waves, and comprising: coding means responsible for constituting parallel:
• interleaving means arranged to interleave, on the one hand, J subsets of parity symbols of each second matrix in J successive sets, and, on the other hand, P subsets of parity symbols of each third matrix in P of these successive sets, and to place in each of the successive sets the respective data of successive bursts received.
• the coding means may for example be responsible for forming the first M matrices by means of a technique known as "multiprotocol encapsulation (MPE)".
• MPE multiprotocol encapsulation
• FEC direct error correction
• FIG. 1 very schematically and functionally illustrates a hybrid transmission infrastructure that makes it possible to implement the invention
• FIG. 2 partially and schematically illustrates an exemplary IP burst data coding according to the invention.
• the attached drawings may not only serve to complete the invention, but also contribute to its definition, if any.
• the object of the invention is to propose a data coding method for the transmission of these data by a wave transmission infrastructure.
• the wave transmission infrastructure is hybrid (PFC, SAT, RA), and more specifically that it is a network.
• DVB-SH type or
• DVB-SSP DVB-SSP
• the invention is not limited to this type of wave transmission infrastructure. It concerns indeed any type of infrastructure for transmitting data (possibly content, possibly multimedia), by wave, to radio communication terminals. Therefore, it may be both a radio communication network and a broadcast network. By way of nonlimiting examples, it may also be a wireless broadcast network (for example a terrestrial network of DVB-H type (for "Digital Video Broadcasting - Handhelds" - mobile TV), or a cellular or mobile network (such as for example a network type
• the radio communication terminals are mobile phones (or cellular) or communicating digital personal assistants (or PDAs).
• the invention is not limited to this type of radio communication terminal. It concerns indeed all communication equipment, fixed or mobile (or portable or cellular), capable at least to receive data over the airwaves via an infrastructure of the aforementioned type.
• a multimedia content receiver such as a decoder, a residential gateway (or “residential gateway”) or a STB ("Set-Top Box”). ")
• a multimedia content receiver such as a decoder, a residential gateway (or “residential gateway") or a STB ("Set-Top Box”).
• the data broadcast to the terminals (TC) are multimedia content data such as television programs.
• multimedia content data such as television programs.
• the invention is not limited to this type of data. It concerns any type of content, including videos, file data (or "data"), signaling data, radio programs, and audio content.
• the implementation of the invention requires the existence of a wave transmission infrastructure, here of the hybrid type and therefore comprising a satellite transmission channel and a communication channel. terrestrial radio transmission.
• the satellite transmission channel comprises a PFC satellite platform (or gateway) for the provision of encoded contents and at least one SAT communication satellite coupled to each other by means of waves.
• the satellite platform PFC is for example coupled to a content server SC which feeds it into contents in the form of bursts (or "bursts"), here of IP type (it could indeed be packet data type NAL (video) or RTP, for example). It is responsible for encoding these received contents by means of a coded CD (implementing a method according to the invention) before transmitting them by waves to the (communication) satellite SAT, which then takes care of the retransmit (broadcast) to TC terminals, either directly or indirectly via the terrestrial radio transmission channel.
• bursts here of IP type (it could indeed be packet data type NAL (video) or RTP, for example).
• This terrestrial radio transmission channel comprises at least one radio access network RA which may for example be part of a mobile (or cellular) communication network.
• this radio access network RA is of the UTRAN (or 3G) type. It therefore mainly comprises N base stations (called Node Bs in the case of a UTRAN) and radio network controllers CR (called RNCs in the case of a UTRAN), connected together, as well as satellite communication PS which is coupled by waves to the satellite SAT (to receive the encoded contents) and wired to the radio network controllers CR (to feed encoded content received.
• the TC terminals can receive the encoded contents either directly from the satellite SAT, when they are not located in a shadow zone, or N base stations, when they are located in a shadow zone.
• Each TC terminal includes a CD codec, similar to that which equips the satellite platform PFC, so as to be able to decode the encoded contents it receives.
• the invention proposes implementing, within the CD codec of the PFC satellite platform, a method of coding the content data received in the form of IP bursts (and more precisely encapsulated in
• the method according to the invention comprises four main steps that are performed by the CD codec when its satellite platform PFC receives bursts of content data (s) from the content server SC.
• a first main step of the method according to the invention consists in forming in parallel M first matrices of T lines and C columns with data subsets of B bursts IP. It will be understood that we operate here by means of sliding windows.
• Each first matrix can be considered as a block of B sub-blocks which each consist of a number of columns of data from a burst IP Si (and constituting a subset of the latter).
• Variable B is at least two. Consequently, the subsets of data of each burst Si are distributed in at least two first successive matrices (Si and Si + 1). For example, the value of B can be three or four or even more.
• the number C of columns of each first matrix is, for example, equal to 191.
• the number T of rows of each first matrix is, for example, at most equal to 1024.
• the first M matrices can for example be constituted by means of the technique called "multiprotocol encapsulation" (or MPE). Note also that when the encoding technique is that which is called MPE-IFEC, each first matrix is what one skilled in the art calls an application data table (ADT). )).
• a second main step of the method according to the invention consists in forming in parallel M second matrices of T lines and N columns with parity symbols which result from an encoding of the data which are respectively contained in the T lines of each of the first Ms. matrices formed during the first main step.
• each second matrix is derived from (and therefore associated with) one of the first M matrices.
• the second M matrices can be constituted at the means of the technique called "direct error correction" (or FEC).
• FEC direct error correction
• the line encoding is of the Reed-Solomon (or RS) type and each second matrix is what the person skilled in the art calls a FEC data table (or FEC Data Table). ).
• the number N of columns of each second matrix is for example equal to 64 (in the case DVB-SH).
• a third main step of the method according to the invention consists in constituting in parallel M third matrices of K rows and C columns with parity symbols which result from an encoding of the data which are respectively contained in the C columns of each of the first Ms. matrices formed during the first main step.
• each third matrix is derived from (and therefore associated with) one of the first M matrices.
• the M third matrices can be formed using the so-called "direct error correction” (FEC) technique.
• FEC direct error correction
• the line encoding is of the Reed-Solomon (or RS) type and each third matrix is what a person skilled in the art calls a data table.
• FEC FEC (or FDT (for "FEC Data Table”)
• the number K of rows of each third matrix is for example equal to 64 (in the case DVB-SH).
• one of the first M matrices can be considered as two complementary parts of a "product matrix” consisting of parity symbols that can be called here "product codes" Cij (i and j denote respectively a row and a column).
• Each row of this product matrix constitutes, for example, a codeword
• each column of this product matrix constitutes for example a codeword
• first, second and third main steps can be implemented by an encoding module MC of the coded CD which equips the PFC satellite platform.
• a fourth main step of the method according to the invention consists in particular of distributing by means of a double interlacing (or “interleaving"), on the one hand, J subsets of parity symbols of each second matrix in J successive sets Ei and, on the other hand, P subsets of parity symbols of each third matrix in P of these successive sets Ei.
• interleaving depth means the number of successive sets of data Ei in which the subsets of parity symbols of a second or third matrix are distributed.
• One of the two variables J and P may be greater than or equal to one, while the other must be greater than or equal to two.
• the value of J can be equal to two or three or even more
• the value of P can be three or four, or even more.
• J may be equal to P, but this is not mandatory.
• the fourth main step also consists in placing in each successive set Ei the respective data of successive bursts Si received.
• Each set Ei produced by the coding method according to the invention is thus finally constituted by at least data of one of the received bursts S 1, subset J subsets of parity symbols from J second matrices and P subassemblies parity symbols from P third matrices.
• FIG. 2 schematically shows an exemplary IP burst data coding performed by means of a CD coding implementing the method according to the invention.
• the variable M is equal to 4
• the variable B is equal to 3
• the variable J is equal to 2
• the variable P is equal to 4.
• the "upper" part of FIG. 2 shows eight salvos S1 to S8 successively received by the satellite platform PFC
• the erroneous bursts are corrected progressively since the above-mentioned sets Ei, which are transmitted successively via the satellite SAT and via the radio access network RA, comprise complementary subsets of parity symbols, and therefore it is necessary to wait to have received at least (B + max (JP) - D) time slots of salvo (sets Ei and FEC associated) to have the completeness parity symbols (FEC) needed to correct the content data of a salvo if initially received by the satellite platform PFC.
• the decoding of the content data (which includes any corrections) is ensured by the CD codecs of the TC terminals.
• the invention is particularly advantageous because it makes it possible to perform an effective correction both in an ITS environment and in a SUB environment. In addition, it reduces the bandwidth used for error correction redundancy because the coding rate is reduced, and therefore it increases the number of services broadcast due to the higher performance offered by the codes. of product regarding error correction. In addition, the invention offers operators more flexibility to size their hybrid infrastructures, as it improves the quality of services and saves bandwidth. Finally, since the interleaving depths (J and P) may be small, the perceived quality of the contents is improved and the switching time between different channel contents (or “zapping time") is reduced (in case of error it is sufficient to wait for a delay equal to min (J, P) to change the channel).
• the invention is not limited to the embodiments of encoding method, coding and platform (or gateway) described above, only by way of example, but it encompasses all the variants that may be considered by the man of art within the scope of the claims below.

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• Probability & Statistics with Applications (AREA)
• Theoretical Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Error Detection And Correction (AREA)
• Detection And Prevention Of Errors In Transmission (AREA)

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• 2009
  • 2009-01-23 FR FR0950416A patent/FR2941580A1/fr active Pending
• 2010
  • 2010-01-19 US US13/145,880 patent/US8677210B2/en not_active Expired - Fee Related
  • 2010-01-19 WO PCT/FR2010/050082 patent/WO2010084283A1/fr active Application Filing
  • 2010-01-19 EP EP10707323A patent/EP2389741A1/fr not_active Withdrawn
  • 2010-01-19 JP JP2011546911A patent/JP2012516099A/ja active Pending

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