WO2025017562A2 - Système et procédé de correction d'erreur directe dans des réseaux de données par satellite - Google Patents

Système et procédé de correction d'erreur directe dans des réseaux de données par satellite Download PDF

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Publication number
WO2025017562A2
WO2025017562A2 PCT/IL2024/050709 IL2024050709W WO2025017562A2 WO 2025017562 A2 WO2025017562 A2 WO 2025017562A2 IL 2024050709 W IL2024050709 W IL 2024050709W WO 2025017562 A2 WO2025017562 A2 WO 2025017562A2
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WO
WIPO (PCT)
Prior art keywords
encoder
code rate
data
turbo
forward connection
Prior art date
Legal status (The legal status 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 status listed.)
Pending
Application number
PCT/IL2024/050709
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English (en)
Other versions
WO2025017562A3 (fr
Inventor
Sorin Goldenberg
Avraham Barda
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ayecka Communication Systems Ltd
Original Assignee
Ayecka Communication Systems Ltd
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.)
Filing date
Publication date
Application filed by Ayecka Communication Systems Ltd filed Critical Ayecka Communication Systems Ltd
Priority to IL325866A priority Critical patent/IL325866A/en
Publication of WO2025017562A2 publication Critical patent/WO2025017562A2/fr
Publication of WO2025017562A3 publication Critical patent/WO2025017562A3/fr
Anticipated expiration legal-status Critical
Pending legal-status Critical Current

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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
    • H04L1/0064—Concatenated codes
    • H04L1/0066—Parallel concatenated codes
    • 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
    • H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
    • H04L1/0002—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the transmission rate
    • 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
    • H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
    • H04L1/0015—Systems modifying transmission characteristics according to link quality, e.g. power backoff characterised by the adaptation strategy
    • 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
    • H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
    • H04L1/0023—Systems modifying transmission characteristics according to link quality, e.g. power backoff characterised by the signalling
    • H04L1/0026—Transmission of channel quality indication
    • 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
    • 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

Definitions

  • the present invention relates generally to Forward Error Correction ( EEC ) techniques , and more particularly to EEC techniques for use in satellite data networks comprising Successive Interference Cancellation ( S IC ) multiple access .
  • EEC Forward Error Correction
  • LEO satellite networks have become a cost- ef fective solution for this demand due to various limitations and drawbacks of alternative solutions such as Geostationary Equatorial Orbit ( GEO) satellites-based networks .
  • Turbo code EEC defined by the Consultative Committee for Space Data Systems ( CCSDS ) is commonly used in LEO satellite data networks so as to cope with low Signal-to-Noise Ratio ( SNR) conditions .
  • CCSDS turbo code schemes are not suf ficiently powerful for loaded network, in particular when Successive Interference Cancellation ( S IC ) multiple access technique is employed .
  • S IC Successive Interference Cancellation
  • the disclosed turbo encoder constitutes an enhancement to code rate 1 / 8 of the known in the art code rate 1 / 6 turbo encoder provided in the CCSDS TM SYNCHRONI ZATION AND CHANNEL CODING RECOMMENDED STANDARD, which comprises two recursive convolutional encoders, an encoder a and an encoder b.
  • Encoder a receives the data to be encoded directly, while encoder b receives the data through an interleaver.
  • QPP quadratic permutation polynomial
  • a method of dynamic code rate control in a data network as described above comprising the steps of: constantly monitoring the Bit Error Rate (BER) of the data received at at least one satellite; and upon detecting that the BER goes below a predetermined threshold, instructing at least part of the earth stations in the network to increase their turbo encoders code rate, e.g. from 1/8 to 1/6, while preserving their transmission symbol rate, so as to alleviate the access contention associated with the SIC at the satellite .
  • BER Bit Error Rate
  • the aforementioned method further comprises the step of instructing said at least part of the earth stations to apply a predetermined delay to the data massages they transmit so as to avoid momentarily increased throughput in the network due to the increased code rate and the resulted shortening of the bursts transmitted from the earth stations .
  • Fig . 1A shows a Prior Art example of a block diagram that schematically illustrates a turbo code encoder intended for earth stations communicating through satellite data networks ;
  • Fig . IB shows a block diagram that schematically illustrates a turbo code encoder intended for earth stations communicating through satellite data networks , in accordance with an embodiment of the present invention
  • Fig . 2 shows a flowchart that schematically illustrates a method of dynamically adj usting the FEC code rate in satellite data networks , in accordance with an embodiment of the present invention
  • Fig . 3 shows a block diagram that schematically illustrates an earth station transmitter, in accordance with an embodiment of the present invention .
  • Embodiments of the present invention provide an enhanced parallel concatenated turbo encoder scheme for earth stations in LEO satellite data networks that employ S IC multiple access .
  • the enhanced encoding is necessity to cope with peak traf fic conditions , which induce too low SIR at the satellite demodulator input .
  • peak traf fic conditions which induce too low SIR at the satellite demodulator input .
  • Conventional elements , aspects and configurations that are not needed for this understanding have been omitted from the figures described below for the sake of simplicity, e.g. satellite-based network architecture and satellite internal stages like demodulator and network management function, but will be apparent to persons of ordinary skill in the art.
  • a code rate 1/6 encoder 100A defined by the CCSDS standard "TM SYNCHRONIZATION AND CHANNEL CODING".
  • the encoder comprises a data buffer 104 that feeds two recursive convolutional encoders: an encoder a, referenced as 108A, directly, and an encoder b, referenced as 112A, through an interleaver block 116A that is separating therebetween, and is also specified by the CCSDS standard.
  • the recursive convolution in each encoder is achieved by a feedback shift register 120, which is connected to backward connection vector GO and to forward connection vectors Gl, G2 and G3.
  • the connection vectors are structured as follows:
  • Buffer 104 output as well as the forward connection vector outputs, are connected to a multiplexing and puncturing block 124A, which is also specified in the CCSDS standard.
  • Fig. IB illustrates the disclosed code rate 1/8 turbo encoder, 100B, which is achieved by modifying the code rate 1/6 encoder, shown in Fig. 1A, as follows:
  • the above vector G4 10111 is added to encoder b 112B rather than to encoder a 108B.
  • Block 124B differs from block 124A by added support to the above new forward connection vectors G2 and G4. Different configurations of block 124B also allow the dynamic code rate control, which is described below with reference to Fig. 2.
  • QPP quadratic permutation polynomial
  • FIG. 2 there is shown a flowchart 200 that schematically illustrates a method of dynamic code rate control, achieved by dynamically adjusting the FEC code rate in satellite data networks comprising SIC multiple access, in accordance with an embodiment of the present invention.
  • the method begins with a setting step 204, in which a satellite onboard network management function (not shown in the figures) commands the network earth stations to set their transmission code rate to the new low rate 1/8.
  • a satellite onboard network management function (not shown in the figures) commands the network earth stations to set their transmission code rate to the new low rate 1/8.
  • the management function checks if the SIR at the satellite demodulator is sufficiently high. This is done by constantly monitoring the Bit Error Rate (BER) of the data received at the satellite. If the BER goes bellow a predetermined threshold BERmin, optionally minus a safety margin ABER, the method proceeds to step 212.
  • BER Bit Error Rate
  • step 212 the management function instructs earth stations that can transmit strongly enough to the satellite to increase their transmission code rate, e.g. to 1/6.
  • the earth stations increase their code rate without decreasing the transmitted symbol rate, so as to alleviate the access contention associated with the SIC at the satellite demodulator, which is achieved due to the shorter transmitted bursts.
  • step 216 the management function also causes an appropriate predetermined delay of the data bursts, either in the satellite or in the earth stations, so as to avoid momentarily increased throughput in the network due to the increased code rate and the resulted shortening of the bursts transmitted from the earth stations.
  • Flowchart 200 returns now to decision step 208.
  • step 208 the management function checks, in a decision step 220, if the BER at the satellite demodulator exceeds the BERmin threshold. If the threshold is not exceeded, the flowchart returns to step 208 and the method process proceeds as explained so far . I f the threshold is exceeded, the flowchart proceeds to step 224 , in which the management function instructs those earth stations that increased their transmission code rate to fall back to a lower code rate . Simultaneously with step 224 , in step 228 the management function also cancels the delay that was introduced in step 216 . Flowchart 200 now returns to decision step 208 and proceeds as explained above .
  • Flowchart 200 is an example flowchart , which was chosen purely for the sake of conceptual clarity . In alternative embodiments , any other suitable flowchart can also be used for illustrating the disclosed method . Method steps that are not mandatory for understanding the disclosed techniques were omitted from Fig . 2 for the sake of simplicity .
  • FIG. 3 there is shown a block diagram 300 that schematically illustrates the transmit part of an earth station, in accordance with a preferred embodiment . Following is a description of the main transmit part blocks .
  • Block 304 represents a 16 byte cycl ic redundancy check ( CRC16 ) to be calculated over the transmit data bytes (not including the CRC itsel f ) .
  • the CRC16 polynomial is x A 16+x A 12+x A 5+ l
  • the CRC is the remainder of the division of the data bytes by the polynomial .
  • Block 308 represents the turbo encoder depicted in Fig . IB .
  • Block 312 represents the aforementioned interleaver 116B, which is actually contained in block 308 though depicted separately in Fig . 3 .
  • Block 316 that follows represents inclusion of known symbols (pilots ) such that to each 80 coded bits a batch of 8 bits of value ' O ' is added . The batch is inserted in the middle such that there are 40 coded bits , 8 pilots and additional 40 coded bits .
  • Block 320 represents a QPSK modulator, which maps each input nibble such that the 1 st bit pair is mapped to the real axis and the 2nd pair is mapped to the imaginary axis , and on each axi s binary 1 is mapped to - 1 and binary 0 is mapped to + 1 .
  • signal spreading is employed as part of the satellite multiple access scheme , which also contains the aforementioned S IC mechanism at the satellite transponder receiver .
  • each QPSK symbol is replicated 32 times .
  • a 3GPP Gold sequence multiplies the resulting stream of step 1 .
  • This sequence has very good orthogonality properties over a period much larger than the maximum duration of a spread frame .
  • Block 324 also applies random cyclic shi fts of the spreading sequence within the transmitted bursts so as to achieve low crosscorrelation between the bursts transmitted from the various earth stations in the data network, even in case of synchroni zed burst transmissions .
  • the transmitter chooses randomly one of four options for the combination preamble + sequence initiali zation option .
  • One of 4 possible preambles are inserted .
  • the initiali zation seeds for Xn for the di f ferent 4 options are :
  • the choice of the preamble creates a separation of about 13db between di f ferent preambles . Due to link budget limitations and power control , such separation is expected to be enough for preventing false detection of the i-th preamble when matched by a correlator to the j -th one ( i ⁇ j ) .
  • a root raised cosine with roll-of f 0 . 2 is used for pulse shaping.
  • the root raised cosine shapes the signal at x2 sampling rate while using a 25 taps filter .
  • Chip Rate 3.84Mchips/sec .

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Quality & Reliability (AREA)
  • Radio Relay Systems (AREA)

Abstract

L'invention concerne un turbo-codeur destiné à être utilisé dans des stations terrestres communiquant par l'intermédiaire de réseaux de données où un accès multiple par annulation d'interférence successive (SIC) vers des satellites en orbite terrestre basse (LEO) est utilisé. Le turbo-codeur décrit constitue une amélioration du débit de code 1/8 d'un turbo-codeur à débit de code 1/6 connu qui comprend deux codeurs convolutifs récursifs, un codeur a et un codeur b. L'amélioration est obtenue en ajoutant deux vecteurs de connexion directe de codeur convolutif récursif au turbo-codeur à débit de code 1/6 comme suit : ajouter le vecteur de connexion directe G4 10111 à l'un ou l'autre du codeur a ou du codeur b; et ajouter le vecteur de connexion directe G2 10101 au codeur b.
PCT/IL2024/050709 2023-07-19 2024-07-18 Système et procédé de correction d'erreur directe dans des réseaux de données par satellite Pending WO2025017562A2 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
IL325866A IL325866A (en) 2023-07-19 2024-07-18 System and method for forward error correction (FEC) in satellite data networks

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US202363514387P 2023-07-19 2023-07-19
US63/514,387 2023-07-19

Publications (2)

Publication Number Publication Date
WO2025017562A2 true WO2025017562A2 (fr) 2025-01-23
WO2025017562A3 WO2025017562A3 (fr) 2025-04-24

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RU2663351C1 (ru) * 2014-11-27 2018-08-03 Хуавэй Текнолоджиз Ко., Лтд. Способ и устройство согласования скорости полярного кода и устройство беспроводной связи
US12137067B2 (en) * 2019-03-15 2024-11-05 Sony Group Corporation Information processing device, information processing method, and communication device
JP7712611B2 (ja) * 2021-04-14 2025-07-24 日本電気株式会社 受信装置および復調のためのパラメータ生成方法
US12323319B2 (en) * 2021-12-14 2025-06-03 Intel Corporation Reliability enhancements for multi-access traffic management

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WO2025017562A3 (fr) 2025-04-24

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