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1. Top results related to forward error correction algorithm

   • Forward Error Correction in Computer Networks

     1. Using Hamming Distance :

     2. Using XOR :

     3. Chunk Interleaving :

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   • Forward error correction in .NET

     Top Answer

     Answered Sep 17, 2010 · 3 votes

     If you have free C++ libraries why don't you try to build CLI wrapper around them?

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     2/5

   • Error detection and error correction algorithm

     Top Answer

     Answered Sep 06, 2011 · 1 votes

     Here is an attempt with some ideas pinched from http://en.wikipedia.org/wiki/Frame_Relay.

     Start off each 64-bit chunk with a fixed header of 01110. Where you have more header info (e.g. sequence number or alternating bit flag, checksum...) you can probably arrange that the bit-pattern 01110 never appears. For arbitrary data, replace any occurrence of 0111 with 01111 - meaning that the effective data rate now depends on the underlying data. Have the provider of data to this layer make sure the data is pretty much random, e.g. by applying a http://en.wikipedia.org/wiki/Randomizer. I think your total data loss here is about 6 bits, which fits with the 6 bits necessary to describe a shift of 0..63.

     In the receiver, look for 01110 to mark the true start of the chunk. If you do not see exactly one such pattern, you know that the chunk has been garbled. I think it takes at least a two-bit error to both destroy an existing 01110 and produce a fake one.

     Garbles that cause chunk misalignment don't look like typical bit garbles, so CRC error rate calculations won't apply out of the box. I would include a non-CRC checksum in each chunk - perhaps a check calculated mod 31 or mod 961 so as to avoid the forbidden 5-bit pattern 01110, although depending on what abuts this you may need to be more restrictive. The chance of an error not being detected would then be about 1 in 31 or 1 in 961, with no particular guarantee about all single errors, unlike polynomial CRC.

     I don't think you have enough space to do per-chunk error correction sensibly, but you could include N error correction chunks after every M ordinary chunks, using e.g. SECDED applied down the columns. You might have e.g. 57 data-bearing chunks and then 6 error correction chunks, treating each payload bit position as bearing 57 data bits and then 6 checksum bits. This should work well if errors tend to corrupt all or none of a single chunk e.g. by causing chunk realignment to fail.

     after comment -

     EDIT

     OK, with one continuously transmitting message you have less bandwidth but relatively more cpu. Two things come to mind:

     1) Given any sort of checksum or other constraint on the message you can achieve some limited error correction by e.g. considering all single bit errors, flipping a bit of the received message, and seeing if the checksum now works.

     2) A message can be checked to see if complies with the bit-stuffing scheme suggested above by looking at only a 5-bit window passed over the message. I think this holds true even if you need to tweak it to work properly at the wraparound. This means that a message can be checked by a BDD of tractable size (Knuth 4A section 7.1.4). This means that you can count the number of 64-bit messages that comply with the bit-stuffing scheme and convert efficiently between message number and message (same section). So you can use this scheme without underlying randomisation or worst-case assumptions about the data to be sent, by just regarding it as an encoding of a number in the range 0..N (where N is to be computed via BDDs) and a 64-bit message. In fact, less elegantly, I think you could use dynamic programming with a 5-bit state instead of BDDs.

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   • When is forward error correction a good idea for packets?

     Top Answer

     Answered Feb 12, 2009 · 5 votes

     I think it's useful for some applications like Voice (VoIP), where you want to avoid errors, and where you never want stop (to retransmit a NAKed packet) and wait (until it's retransmitted).

     So it might be implemented on top of the Real-time Transport Protocol flavour of UDP.

     Wouldn't it be terrible for latency?

     Are you asking whether forward error correction increases end-to-end delay? If so, I think the answer is "no", but it does increase the needed bandwidth.

     I believe you always already need some latency, to avoid jitter; so for example, you might say "let's delay the whole voice channel by 200 msec, so any/every packet can take from 0 to 200 msec to cross the internet, and be reassembled and sent through the D-to-A converter at the other end."

     Given those numbers, then having no forward error correction might mean that, in each 200 msec period, you send 10 packets each containing 20 msec of data ... and if one is lost, then that's a gap (a glitch) at the other end.

     Whereas, having some forward error correction might mean that, in each 200 msec period, you still send 10 packets ... each packet contains 20 msec of data, plus 10 msec of data that's already been transmitted in another packet (or, maybe you send 30 packets instead of 20). Then, if any single packet is lost, the data which it carried was delivered redundently (half in each of two other packets), which avoids any glitch in the decoded output.

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   • forward backward algorithm pseudocode clarification

     Top Answer

     Answered Feb 09, 2017 · 0 votes

     This might be a little late. The goal of this algorithm is to inference on data given the model. By this calculation you are calculating the posterior probability of P(x_i|o_i) which can help finding out the next step in the test procedure.

     Hope that has helped.

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2. People also ask

   What is forward error correction (FEC)?

   • Forward Error Correction (FEC): Instead of sending again, FEC adds redundancy into transmitted data enabling receivers correct mistakes on their own. Reed-Solomon codes and Hamming codes are some examples of FEC methods. Acknowledgment and Retransmission: Messages like Acknowledgment (ACK) and negative acknowledgment (NAK) play a big role here.

   How Error Correction is Done? - GeeksforGeeks

   www.geeksforgeeks.org/how-error-correction-is-done/

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   What are error correction algorithms?

   • Error Correction Algorithms: The Viterbi algorithm for convolutional codes and the Reed-Solomon algorithm for block codes, among others, are used to mathematically recover data from damaged transmissions.

   How Error Correction is Done? - GeeksforGeeks

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   Is error-correction bound exact?

   • However, this error-correction bound is not exact. In 1999, Madhu Sudan and Venkatesan Guruswami at MIT published "Improved Decoding of Reed–Solomon and Algebraic-Geometry Codes" introducing an algorithm that allowed for the correction of errors beyond half the minimum distance of the code.

   Reed–Solomon error correction - Wikipedia

   en.wikipedia.org/wiki/Reed–Solomon_error_correction

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   What is error correction in computer networks?

   • In summary, error correction in computer networks is a complex process that includes error detection, retransmission and proactive correction methods. These techniques help improve network reliability and data integrity. "GeeksforGeeks helped me ace the GATE exam!

   How Error Correction is Done? - GeeksforGeeks

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3. en.wikipedia.org › wiki › Reed–Solomon_errorReed–Solomon error correction - Wikipedia

   en.wikipedia.org › wiki › Reed–Solomon_error

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   May 20, 2024 · Reed–Solomon codes are also used in xDSL systems and CCSDS's Space Communications Protocol Specifications as a form of forward error correction. Space transmission Deep-space concatenated coding system. Notation: RS(255, 223) + CC ("constraint length" = 7, code rate = 1/2).

4. dl.acm.org › doi › abs8-bit forward error correction codes in linear network coding

   dl.acm.org › doi › abs

   May 13, 2024 · Using mathematical modeling, the probability characteristics of the considered 8-bit forward error correction codes are calculated for two network topologies used in network coding systems. Recommendations on the use of the considered codes are given. Supplemental Material. Available for Download.

5. www.geeksforgeeks.org › how-error-correction-is-doneHow Error Correction is Done? - GeeksforGeeks

   www.geeksforgeeks.org › how-error-correction-is-done

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   May 14, 2024 · Forward Error Correction (FEC): Instead of sending again, FEC adds redundancy into transmitted data enabling receivers correct mistakes on their own. Reed-Solomon codes and Hamming codes are some examples of FEC methods. Acknowledgment and Retransmission: Messages like Acknowledgment (ACK) and negative acknowledgment (NAK) play a big role here.

6. Videos

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     Error Detection and Correction 3: Forward Error Correction

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     Forward Error Correction FEC - Computer Networks

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7. arxiv.org › pdf › 2405Linear Logic and Quantum Error Correcting Codes - arXiv.org

   arxiv.org › pdf › 2405

   1 day ago · Remark 3.16.The error-correction procedure Pitself can be thought of as denoting the codespace, since codewords are characterised by the condition c=P(c). If we have two error-correcting codes H′ ⊆H with the same codespace C, then the respectively error-correction procedures P,P′ have “the same denotation but different senses”. The senses

8. en.wikipedia.org › wiki › BackpropagationBackpropagation - Wikipedia

   en.wikipedia.org › wiki › Backpropagation

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   May 23, 2024 · Error backpropagation has been suggested to explain human brain ERP components like the N400 and P600. In 2023, a backpropagation algorithm was implemented on a photonic processor by a team at Stanford University. See also. Artificial neural network; Neural circuit; Catastrophic interference; Ensemble learning; AdaBoost; Overfitting

9. www.ece.unb.ca › tervo › ee4253ECE4253 Error Control Codes - UNB

   www.ece.unb.ca › tervo › ee4253

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   May 24, 2024 · This is called Forward Error Correction (FEC). Ultimately, even the proposed send-the-data-three-times approach can fail if multiple bit errors overwhelm the error control scheme. In that case, two copies may have the same error and the wrong correction is made or perhaps all three copies are completely different and no correction is possible ...

10. resources.goanritsu.com › digital-and-opticalStress Testing PCIe 6.0 FLIT-based Forward Error Correction

    resources.goanritsu.com › digital-and-optical

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    2 days ago · PCIe 6.0 introduces Flow Control Unit (FLIT) encoding to allow forward error correction (FEC) on fixed-size packets. Stress testing PCIe hardware includes addressing this new protocol approach. Once FLIT mode is turned on, it will work with any data rate.

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