Concatenated Forward Error Correction
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(Discuss) Proposed since January 2015. In telecommunication, information theory, and coding theory, forward error correction (FEC) or channel coding[1] is a technique used for controlling errors in data transmission over unreliable
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or noisy communication channels. The central idea is the sender encodes the message forward error correction ppt in a redundant way by using an error-correcting code (ECC). The American mathematician Richard Hamming pioneered this field in
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the 1940s and invented the first error-correcting code in 1950: the Hamming (7,4) code.[2] The redundancy allows the receiver to detect a limited number of errors that may occur anywhere in the forward error correction algorithm message, and often to correct these errors without retransmission. FEC gives the receiver the ability to correct errors without needing a reverse channel to request retransmission of data, but at the cost of a fixed, higher forward channel bandwidth. FEC is therefore applied in situations where retransmissions are costly or impossible, such as one-way communication links and when transmitting to multiple receivers in multicast. forward error correction rate FEC information is usually added to mass storage devices to enable recovery of corrupted data, and is widely used in modems. FEC processing in a receiver may be applied to a digital bit stream or in the demodulation of a digitally modulated carrier. For the latter, FEC is an integral part of the initial analog-to-digital conversion in the receiver. The Viterbi decoder implements a soft-decision algorithm to demodulate digital data from an analog signal corrupted by noise. Many FEC coders can also generate a bit-error rate (BER) signal which can be used as feedback to fine-tune the analog receiving electronics. The noisy-channel coding theorem establishes bounds on the theoretical maximum information transfer rate of a channel with some given noise level. Some advanced FEC systems come very close to the theoretical maximum. The maximum fractions of errors or of missing bits that can be corrected is determined by the design of the FEC code, so different forward error correcting codes are suitable for different conditions. Contents 1 How it works 2 Averaging noise to reduce errors 3 Types of FEC 4 Concatenated FEC codes for improved performance 5 Low-density parity-check
feedback return to old SpringerLink Frontiers of Optoelectronics in ChinaSeptember 2008, Volume
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1, Issue 1, pp 20–24Forward error correction concatenated code in DWDM forward error correction library systemsAuthorsAuthors and affiliationsJianguo YuanEmail authorZe JiangYouju MaoWenwei YeResearch ArticleFirst Online: 09 October 2008DOI: 10.1007/s12200-008-0056-7Cite this article as: Yuan,
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J., Jiang, Z., Mao, Y. et al. Front. Optoelectron. China (2008) 1: 20. doi:10.1007/s12200-008-0056-7 1 Citations 37 Views AbstractThe three concatenated coding schemes of the https://en.wikipedia.org/wiki/Forward_error_correction inner-outer type, the parallel type and the consecutive type to improve the current forward error correction (FEC) coding technologies are proposed for dense wavelength-division multiplexing (DWDM) systems, after introducing the development trend of DWDM optical communication systems. The concatenated code is theoretically analyzed. The theoretical analyses and simulation results http://link.springer.com/article/10.1007/s12200-008-0056-7 show that inner-outer concatenated code has a greater redundancy and the decoding of parallel concatenated code is too complex. However, consecutive concatenated code is superior coding scheme with advantages such as better error correction performance, moderate redundancy and easy implementation, therefore it could be better used in high-speed and long-haul DWDM systems.Keywordsdense wavelength-division multiplexing (DWDM) systemsuper forward error correction (Super-FEC)concatenated codenet coding gain (NCG)__________Translated from Laser Journal, 2007, 28(2): 67–69 [译自: 激光杂志]References1.ITU-T G. 975. Forward Error Correction for Submarine Systems. 19962.ITU-T G. 709. Network Node Interface for the Optical Transport Network (OTN). 19983.Bosco G, Montorsi G, Benedetto S. Soft decoding in optical systems. IEEE Transactions on Communications, 2003, 51(8): 1258–1265CrossRef4.Katayama Y, Yamane T. Concatenation of interleaved binary/non-binary block codes for improved forward error correction. In: OFC 2003. 2003, 391–3935.Huettinger S, Huber J. Performance estimation for concatenated coding schemes. In: Proceedings of IEEE Information Theory W
Request full-text Forward error correction concatenated code in DWDM systemsArticle in Frontiers of Optoelectronics in China 1(1):20-24 · September 2008 with 32 https://www.researchgate.net/publication/227048009_Forward_error_correction_concatenated_code_in_DWDM_systems ReadsDOI: 10.1007/s12200-008-0056-7 1st Jianguo Yuan15.89 · Chongqing University of http://www.wanoptimization.org/forward_error_correction.php Posts and Telecommunications2nd Ze Jiang3rd Youju Mao4th Wenwei YeAbstractThe three concatenated coding schemes of the inner-outer type, the parallel type and the consecutive type to improve the current forward error correction (FEC) coding technologies are proposed for dense wavelength-division multiplexing forward error (DWDM) systems, after introducing the development trend of DWDM optical communication systems. The concatenated code is theoretically analyzed. The theoretical analyses and simulation results show that inner-outer concatenated code has a greater redundancy and the decoding of parallel concatenated code is too complex. However, consecutive concatenated code is superior coding forward error correction scheme with advantages such as better error correction performance, moderate redundancy and easy implementation, therefore it could be better used in high-speed and long-haul DWDM systems.Do you want to read the rest of this article?Request full-text CitationsCitations3ReferencesReferences5Free-Space Optical Communications in Turbulent Channels"It is a special method by which a long code can consist of some short codes. Concatenated RS codes are used to improve the burst error correction capability [8, 9]. For a higher bit rate in optical communications, APD is frequently the photodetector of choice due to its internal gain which provides better sensitivity than PIN photodiode. "[Show abstract] [Hide abstract] ABSTRACT: The atmospheric turbulence effect on free-space optical (FSO) communications is one of the biggest problems that face FSO systems. Atmospheric turbulence is the fluctuations of the signal due to the changing of refractive index which results from those air particles which are not homogono
correction techniques consist of sending redundant data and the receiver or destination on recognizing portions of the data that are effort free. Forward error correction does not require a handshake between sender and receiver and this allows for the transmission of data to multiple destinations from a single source. Since a part of the original transmission is redundant data, it allows the destination to detect and correct a limited number of errors. These errors can be corrected without retransmission. While forward error correction gives the ability to do this, it comes at a cost. The bandwidth required at the origin is higher because redundant data has to be transmitted. Therefore forward error correction techniques are only applied in situations where retransmissions are costly or impossible in instances where data is being broadcast to multiple destinations. As stated earlier, forward error correction adds redundancy to the transmitted data stream using a predetermined algorithm. A complex function of the original data may be used to form the redundant bit and the original data may or may not appear literally in the coded output. If a code includes unmodified input data in the output it is called systematic and those that are modified are called non-systematic. Several types of forward error correction exisit and the following is a brief overview of these. Types of Forward Error Correction Block and convolutional codes are the two main categories of forward error correction codes. Sometimes these are combined in concatenated coding schemes. Block codes – this type of forward error correction works on fixed block sizes or symbols of predetermined size. These are generally decoded in polynomial time to their length. Convolutional codes – this type of forward error correction works on data of arb