“Viterbi decoding” papers

Convolution Coding and Viterbi Decoding

Chaguri, Hari Kiran · PEARL (University of Plymouth) · 2010

Convolutional encoding with Viterbi decoding is a FEC technique that is particularly\nsuited to a channel in which the transmitted signal is corrupted mainly by additive\nwhite Gaussian noise (AWGN). You can think of AWGN as noise whose voltage\ndistribution over time has characteristics that can be described using a Gaussian, or\nnormal, statistical distribution, i.e. a bell curve. This voltage distribution has zero\nmean and a standard deviation that is a function of the signal-to-noise ratio (SNR) of\nthe received signal. Let's assume for the moment that the received signal level is\nfixed. Then if the SNR is high, the standard deviation of the noise is small, and viceversa.\nIn digital communications, SNR is usually measured in terms of Eb/No, which\nstands for energy per bit divided by the one-sided noise density.\nThis Project presents the importance of Viterbi Decoder for a convolution encoder\nand theory behind their success in deep mobile and space communications. This\nproject describes the necessary building blocks for implementing convolution codes.\nEmphasis is focused on implementation of generalized Viterbi Decoder of rate V2 with\ndifferent values of ' K ' (3, 5, 7, and 9). A Soft decision Viterbi Decoder is\nimplemented in ' C language due to its simplicity and fast processing. The results\nobtained from the simulation shows that the error performance increases with the\nincrease of constraint length. Suitable graphs are provided for comparing the error\nperformance.\nIn the simulation part of convolution codes a rate '/z encoder is used for\nsimplicity. The channel used was AWGN channel. Decoding is done by Viterbi\ndecoder which uses Soft decision and the input to the Viterbi decoder (channel\noutput) is quantized and decoded.\nA thorough discussion of convolution encoder, Viterbi algorithm and Viterbi decoder\nis done and all the portion of the thesis is well discussed illustrating with block\ndiagrams and flow charts wherever needed. The results of the implemented system are\nwell discussed giving the screenshots of the output at different stages of the results.\nFinally the project reviews the direction of research in mobile communications and\nsatellite communications. The limitations of Convolution codes and Viterbi decoder\nare also mentioned.

Cited by 0

Convolutional Encoding and Viterbi Decoding

EHALAIVAN, SELVARAJAH · Zenodo (CERN European Organization for Nuclear Research) · 2003

We introduce the notion of innovations for Viterbidecoding of convolutional codes. First we define a kind of innovationcorresponding to the received data, i.e., the input to a Viterbidecoder. Then the structure of a Scarce-State-Transition (SST)Viterbi decoder is derived in a natural manner. It is shown thatthe newly defined innovation is just the input to the main decoderin an SST Viterbi decoder and generates the same syndromeas the original received data does. A similar result holds forQuick-Look-In (QLI) codes as well. In this case, however, theprecise innovation is not defined. We see that this innovationlikequantity is related to the linear smoothed estimate of theinformation. The essence of innovations approach to a linearfiltering problem is first to whiten the observed data, and thento treat the resulting simpler white-noise observations problem.In our case, this corresponds to the reduction of decodingcomplexity in the main decoder in an SST Viterbi decoder. Weshow the distributions related to the main decoder (i.e., theinput distribution and the state distribution in the code trellisfor the main decoder) are much biased under moderately noisyconditions. We see that these biased distributions actually lead tothe complexity reduction in the main decoder. Furthermore, it isshown that the proposed innovations approach can be extendedto maximum-likelihood (ML) decoding of block codes as well

Cited by 0Open access

Truncation effects in Viterbi decoding

Robert J. McEliece, I. Onyszchuk · 2003

Practical Viterbi decoders often fall significantly short of full maximum likelihood decoding performance because of survivor truncation effects. In the present work the authors study the tradeoff between truncation length and performance loss for the two most common variations of Viterbi's algorithm: best-state decoding (BSD) and fixed-state decoding (FSD). It is found that FSD survivors should be about twice as long as BSD survivors for comparable performance.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>

Cited by 17

Performance of analog Viterbi decoding

Kai He, Gert Cauwenberghs · 2003

We propose the Binary-Analog Channel (BAC) as a model for a binary communication channel accounting for analog saturation effects, and use the model to analyze analog Viterbi decoding. We also model imperfections in the VLSI implementation of the analog decoder, to estimate practical performance. Extensive random coding simulations indicate that an analog Viterbi decoder implemented in a typical CMOS process easily outperforms its digital counterpart with 3-bit or higher soft-decision decoding resolution.

Cited by 9

Improvement of Viterbi Decoding Algorithm

Lihua Li · 2009

Viterbi algorithm decoding is a kind of maximum likelihood decoding.In this paper,the improvement of Viterbi algorithm is produced.The experiment results show that it can overcome the drawback of the decoding performance greatly degraded,when burst errors occur,and reduce the decoding complexity while the good characteristic of conventional Viterbi algorithm remains uncharged.Simulations over coding channel show that the more correct bits we know the better the performance is.

Cited by 0

Problem: ASR decoding without Viterbi

Markov Chain, Monte Carlo, Kevin Duh et al. · 2013

E f ( x) p( x) dx X arg max p( x) x • Situation suitable for MCMC: – Direct integration/optimization is hard: • X is a large space or f(x) is complex – P(x) is easily computed (up to normalization constant)

Cited by 0

Burst Statistics of Viterbi Decoding

L. J. Deutsch, Robert Miller · NASA Technical Reports Server (NASA) · 1981

A mathematical model of Viterbi decoder burst error performance is presented. This model allows for computer generation of Viterbi-like error sequences quickly and inexpensively for applications where large amounts of data are required. The model is corroborated through comparisons with actual software decoder simulations.

Cited by 12

Convolutional Encoding and Viterbi Decoding

EHALAIVAN, SELVARAJAH · Zenodo (CERN European Organization for Nuclear Research) · 2003

We introduce the notion of innovations for Viterbidecoding of convolutional codes. First we define a kind of innovationcorresponding to the received data, i.e., the input to a Viterbidecoder. Then the structure of a Scarce-State-Transition (SST)Viterbi decoder is derived in a natural manner. It is shown thatthe newly defined innovation is just the input to the main decoderin an SST Viterbi decoder and generates the same syndromeas the original received data does. A similar result holds forQuick-Look-In (QLI) codes as well. In this case, however, theprecise innovation is not defined. We see that this innovationlikequantity is related to the linear smoothed estimate of theinformation. The essence of innovations approach to a linearfiltering problem is first to whiten the observed data, and thento treat the resulting simpler white-noise observations problem.In our case, this corresponds to the reduction of decodingcomplexity in the main decoder in an SST Viterbi decoder. Weshow the distributions related to the main decoder (i.e., theinput distribution and the state distribution in the code trellisfor the main decoder) are much biased under moderately noisyconditions. We see that these biased distributions actually lead tothe complexity reduction in the main decoder. Furthermore, it isshown that the proposed innovations approach can be extendedto maximum-likelihood (ML) decoding of block codes as well

Cited by 0Open access

List Viterbi Decoding of PAC Codes

Mohammad Rowshan, Emanuele Viterbo · 2020

<div>Polarization-adjusted convolutional (PAC) codes are special concatenated codes in which we employ a one-to-one convolutional transform as a pre-coding step before the polar transform. In this scheme, the polar transform (as a mapper) and the successive cancellation process (as a demapper) present a synthetic vector channel to the convolutional transformation. The numerical results show that this concatenation improves the Hamming distance properties of polar codes. </div><div>In this work, we implement the parallel list Viterbi algorithm (LVA) and show how the error correction performance moves from the poor performance of the Viterbi algorithm (VA) to the superior performance of list decoding by changing the constraint length, list size, and the sorting strategy (local sorting and global sorting) in the LVA. Also, we analyze the latency of the local sorting of the paths in LVA relative to the global sorting in the list decoding and the trade-off between the sorting latency and the error correction performance.</div>

Cited by 7Open access

Viterbi Decoding Circuit for DVD Players

Hideki Hayashi, M. Umezawa, Hiroshi Kobayashi · Joint International Symposium on Optical Memory and Optical Data Storage · 1996

The DVD has the highest recording density in the optical discs of practical use. From such a high density medium, it is difficult to reproduce digital data accurately. We coped with this by developing a Viterbi decoding circuit for DVD players. In the following, we will outline the structure and the efficiency of the Viterbi decoder.

Cited by 4

Viterbi decoding of ternary line codes

Khmaies Ouahada, H.C. Ferreira · 2004

The Viterbi decoding algorithm provides maximum likelihood decoding and has found widespread application since its introduction in 1967. It is currently the most widely used technique for the decoding of codes having a state system description, including the class of linear error correcting convolutional codes. Contrary to this, it is still common practice to use combinational logic decoders for ternary line codes. These are non-linear codes frequently used in metallic cable systems due to advantages such as efficient utilization of bandwidth, and a DC free power spectral density function. We investigate in this paper the behaviour of Viterbi decoding for the most important ternary line codes, and the coding gain that can be obtained by applying soft-decision decoding. The simplification of the Viterbi decoding implementation and the reduction in latency by shortening its survivor path length, have also been investigated.

Cited by 6

Truncation Error Probability in Viterbi Decoding

F. Hemmati, Daniel J. Costello · IEEE Transactions on Communications · 1977

An upper bound on the bit error probability due to truncation of the path length in Viterbi decoding is obtained for any given convolutional code. This bound is then used to determine the path length at which the additional error probability due to truncation becomes negligible compared to the maximum likelihood decoding error probability. These results are tested by simulation using several short constraint length codes.

Cited by 53

List Viterbi Decoding of PAC Codes

Mohammad Rowshan, Emanuele Viterbo · 2020

<div>Polarization-adjusted convolutional (PAC) codes are special concatenated codes in which we employ a one-to-one convolutional transform as a pre-coding step before the polar transform. In this scheme, the polar transform (as a mapper) and the successive cancellation process (as a demapper) present a synthetic vector channel to the convolutional transformation. The numerical results show that this concatenation improves the Hamming distance properties of polar codes. </div><div>In this work, we implement the parallel list Viterbi algorithm (LVA) and show how the error correction performance moves from the poor performance of the Viterbi algorithm (VA) to the superior performance of list decoding by changing the constraint length, list size, and the sorting strategy (local sorting and global sorting) in the LVA. Also, we analyze the latency of the local sorting of the paths in LVA relative to the global sorting in the list decoding and the trade-off between the sorting latency and the error correction performance.</div>

Cited by 5Open access

List Viterbi Decoding of PAC Codes

Mohammad Rowshan, Emanuele Viterbo · 2021

<div>Polarization-adjusted convolutional (PAC) codes are special concatenated codes in which we employ a one-to-one convolutional transform as a pre-coding step before the polar transform. In this scheme, the polar transform (as a mapper) and the successive cancellation process (as a demapper) present a synthetic vector channel to the convolutional transformation. The numerical results show that this concatenation improves the Hamming distance properties of polar codes. </div><div>In this work, we implement the parallel list Viterbi algorithm (LVA) and show how the error correction performance moves from the poor performance of the Viterbi algorithm (VA) to the superior performance of list decoding by changing the constraint length, list size, and the sorting strategy (local sorting and global sorting) in the LVA. Also, we analyze the latency of the local sorting of the paths in LVA relative to the global sorting in the list decoding and the trade-off between the sorting latency and the error correction performance.</div>

Cited by 4Open access

Decoding convolutional codes by Viterbi algorithm

Jiří Lechner · Digital Repository (National Repository of Grey Literature) · 2008

Cited by 0

Feedforward Architectures for Parallel Viterbi Decoding

Gerhard Fettweis, H. Meyr · 1991

Cited by 3

SST data transmitted utilising Viterbi decoding

F. Steyn, J.S. Kunicki, H.C. Fereira · 2002

Education is of great importance for a country's successful development. Distance education is seen by many as a solution to the education of disadvantaged communities in Africa. Distance education based on SST (supplementary signal transmission) can successfully address most of the associated problems. This paper concentrates on results obtained from measurements done on a "real-world" SST channel. Being a radio channel the SST channel is very noisy and for reliable data transmission FEC (forward error correction) codes are essential. The noise properties of the channel are measured, including and excluding FEC. BER (bit error rate) was measured without use of FEC, to demonstrate the problem, and then reevaluated to indicate effect of FEC on the noise corrupted data.

Cited by 0

Viterbi-decoding differential detection of DPSK

Fumiyuki Adachi, Mamoru Sawahashi · Electronics Letters · 1992

Differential detection based on MLSE using the Viterbi algorithm (Viterbi-decoding DD) is proposed and the BER performance of 2DPSK under AWGN channels is investigated by computer simulation. It is shown that the performance loss in the required Eb/N0 of the proposed Viterbi-decoding DD compared with ideal coherent detection with differential decoding is only around 0.15dB at BER = 10−3.

Cited by 32

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