The Experts below are selected from a list of 2547 Experts worldwide ranked by ideXlab platform
S Kallel - One of the best experts on this subject based on the ideXlab platform.
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sequential decoding with an efficient Incremental Redundancy arq scheme
IEEE Transactions on Communications, 1992Co-Authors: S KallelAbstract:Sequential decoding is analyzed in conjunction with an efficient Incremental Redundancy automatic repeat request (ARQ) scheme using punctured convolutional coding. With the Incremental Redundancy ARQ scheme, whenever the decoding time of a given data packet exceeds some predetermined value T/sub max/, decoding of that data packet is stopped and Incremental Redundancy bits are provided by the transmitter, a few bits at a time, as needed. It is shown that the Incremental Redundancy ARQ scheme provides throughput improvement over the partial retransmission code combining ARQ scheme. The advantage of the Incremental Redundancy ARQ scheme is that the throughput increases as the starting coding rate increases over all ranges of signal-to-noise ratios. >
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analysis of memory and Incremental Redundancy arq schemes over a nonstationary channel
IEEE Transactions on Communications, 1992Co-Authors: S KallelAbstract:A generalized type II automatic-repeat-request (ARQ) scheme using punctured convolutional coding on a two-state Markov model of a nonstationary channel is analyzed. A simple ARQ scheme with memory is also analyzed. It is shown that the simple memory ARQ scheme offers a substantial throughput improvement over a conventional ARQ scheme at severe channel conditions. Furthermore, the generalized type II ARQ scheme yields a better performance than the conventional type II ARQ scheme under all channel conditions, thus making it attractive for use over time-varying channels. >
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an adaptive Incremental Redundancy selective repeat arq scheme for finite buffer receivers
International Conference on Computer Communications, 1991Co-Authors: S Kallel, C LeungAbstract:An Incremental Redundancy selective-repeat ARQ (automatic-repeat-request) scheme, called the AIR (adaptive Incremental Redundancy) scheme, for use in systems with limited buffer receivers, based on the use of punctured convolutional codes, is introduced. Its throughput is compared to that of E. J. Weldon's (1982) scheme and a type-II ARQ scheme studied previously by the authors (1990). The AIR scheme is found to have a relatively good throughput over a wide range of channel conditions, thus making it attractive for use on time-varying channels. >
Ali Chelli - One of the best experts on this subject based on the ideXlab platform.
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unified performance analysis of hybrid arq with Incremental Redundancy over free space optical channels
Personal Indoor and Mobile Radio Communications, 2014Co-Authors: Emna Zedini, Ali Chelli, Mohamedslim AlouiniAbstract:In this paper, we carry out a unified performance analysis of hybrid automatic repeat request (HARQ) with Incremental Redundancy (IR) from an information theoretic perspective over a point-to-point free-space optical (FSO) system. First, we introduce a novel unified expression for the distribution of a single FSO link modeled by the Gamma fading that accounts for pointing errors subject to both types of detection techniques at the receiver side (i.e. heterodyne detection and intensity modulation with direct detection (IM/DD)). Then, we provide analytical expressions for the outage probability, the average number of transmissions, and the average transmission rate for HARQ with IR, assuming a maximum number of rounds for the HARQ protocol. In our study, the communication rate per HARQ round is constant. Our analysis demonstrates the importance of HARQ in improving the performance and reliability of FSO communication systems. All the given results are verified via computer-based Monte-Carlo simulations.
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performance and delay analysis of hybrid arq with Incremental Redundancy over double rayleigh fading channels
IEEE Transactions on Wireless Communications, 2014Co-Authors: Ali Chelli, John R. Barry, Emna Zedini, Mohamedslim Alouini, Matthias PatzoldAbstract:In this paper, we study the performance of hybrid automatic repeat request (HARQ) with Incremental Redundancy over double Rayleigh channels, a common model for the fading amplitude of vehicle-to-vehicle communication systems. We inves- tigate the performance of HARQ from an information theoretic perspective. Analytical expressions are derived for the -outage capacity, the average number of transmissions, and the average transmission rate of HARQ with Incremental Redundancy assum- ing a maximum number of HARQ rounds. Moreover, we evaluate the delay experienced by Poisson arriving packets for HARQ with Incremental Redundancy. We provide analytical expressions for the expected waiting time, the packet's sojourn time in the queue, the average consumed power, and the energy efficiency. In our study, the communication rate per HARQ round is adjusted to the average signal-to-noise ratio (SNR) such that a target outage prob- ability is not exceeded. This setting conforms with communication systems in which a quality of service is expected regardless of the channel conditions. Our analysis underscores the importance of HARQ in improving the spectral efficiency and reliability of communication systems. We demonstrate as well that the explored HARQ scheme achieves full diversity. Additionally, we investigate the tradeoff between energy efficiency and spectral efficiency. Index Terms—Hybrid automatic repeat request (HARQ), incre- mental Redundancy, energy efficiency, delay analysis, information outage capacity, average transmission rate, average number of transmissions.
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on the performance analysis of hybrid arq with Incremental Redundancy and with code combining over free space optical channels with pointing errors
IEEE Photonics Journal, 2014Co-Authors: Emna Zedini, Ali Chelli, Mohamedslim AlouiniAbstract:In this paper, we investigate the performance of hybrid automatic repeat request (HARQ) with Incremental Redundancy (IR) and with code combining (CC) from an information-theoretic perspective over a point-to-point free-space optical (FSO) system. First, we introduce new closed-form expressions for the probability density function, the cumulative distribution function, the moment generating function, and the moments of an FSO link modeled by the Gamma fading channel subject to pointing errors and using intensity modulation with direct detection technique at the receiver. Based on these formulas, we derive exact results for the average bit error rate and the capacity in terms of Meijer's G functions. Moreover, we present asymptotic expressions by utilizing the Meijer's G function expansion and using the moments method, too, for the ergodic capacity approximations. Then, we provide novel analytical expressions for the outage probability, the average number of transmissions, and the average transmission rate for HARQ with IR, assuming a maximum number of rounds for the HARQ protocol. Besides, we offer asymptotic expressions for these results in terms of simple elementary functions. Additionally, we compare the performance of HARQ with IR and HARQ with CC. Our analysis demonstrates that HARQ with IR outperforms HARQ with CC.
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performance analysis of hybrid arq with Incremental Redundancy over amplify and forward dual hop relay channels
arXiv: Information Theory, 2014Co-Authors: Ali Chelli, Amir Hadjtaieb, Mohamedslim AlouiniAbstract:In this paper, we consider a three node relay network comprising a source, a relay, and a destination. The source transmits the message to the destination using hybrid automatic repeat request (HARQ) with Incremental Redundancy (IR). The relay overhears the transmitted message, amplifies it using a variable gain amplifier, and then forwards the message to the destination. This latter combines both the source and the relay message and tries to decode the information. In case of decoding failure, the destination sends a negative acknowledgement. A new replica of the message containing new parity bits is then transmitted in the subsequent HARQ round. This process continues until successful decoding occurs at the destination or a maximum number $M$ of rounds is reached. We study the performance of HARQ-IR over the considered relay channel from an information theoretic perspective. We derive exact expressions and bounds for the information outage probability, the average number of transmissions, and the average transmission rate. Moreover, we evaluate the delay experienced by Poisson arriving packets over the considered relay network. We also provide analytical expressions for the expected waiting time, the sojourn time, and the energy efficiency. The derived exact expressions are validated by Monte Carlo simulations.
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on the performance of hybrid arq with Incremental Redundancy and with code combining over relay channels
IEEE Transactions on Wireless Communications, 2013Co-Authors: Ali Chelli, Mohamedslim AlouiniAbstract:In this paper, we consider a relay network consisting of a source, a relay, and a destination. The source transmits a message to the destination using hybrid automatic repeat request (HARQ). The relay overhears the transmitted messages over the different HARQ rounds and tries to decode the data packet. In case of successful decoding at the relay, both the relay and the source cooperate to transmit the message to the destination. The channel realizations are independent for different HARQ rounds. We assume that the transmitter has no channel state information (CSI). Under such conditions, power and rate adaptation are not possible. To overcome this problem, HARQ allows the implicit adaptation of the transmission rate to the channel conditions by the use of feedback. There are two major HARQ techniques, namely HARQ with Incremental Redundancy (IR) and HARQ with code combining (CC). We investigate the performance of HARQ-IR and HARQ-CC over a relay channel from an information theoretic perspective. Analytical expressions are derived for the information outage probability, the average number of transmissions, and the average transmission rate. We illustrate through our investigation the benefit of relaying. We also compare the performance of HARQ-IR and HARQ-CC and show that HARQ-IR outperforms HARQ-CC.
Mohamedslim Alouini - One of the best experts on this subject based on the ideXlab platform.
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unified performance analysis of hybrid arq with Incremental Redundancy over free space optical channels
Personal Indoor and Mobile Radio Communications, 2014Co-Authors: Emna Zedini, Ali Chelli, Mohamedslim AlouiniAbstract:In this paper, we carry out a unified performance analysis of hybrid automatic repeat request (HARQ) with Incremental Redundancy (IR) from an information theoretic perspective over a point-to-point free-space optical (FSO) system. First, we introduce a novel unified expression for the distribution of a single FSO link modeled by the Gamma fading that accounts for pointing errors subject to both types of detection techniques at the receiver side (i.e. heterodyne detection and intensity modulation with direct detection (IM/DD)). Then, we provide analytical expressions for the outage probability, the average number of transmissions, and the average transmission rate for HARQ with IR, assuming a maximum number of rounds for the HARQ protocol. In our study, the communication rate per HARQ round is constant. Our analysis demonstrates the importance of HARQ in improving the performance and reliability of FSO communication systems. All the given results are verified via computer-based Monte-Carlo simulations.
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performance and delay analysis of hybrid arq with Incremental Redundancy over double rayleigh fading channels
IEEE Transactions on Wireless Communications, 2014Co-Authors: Ali Chelli, John R. Barry, Emna Zedini, Mohamedslim Alouini, Matthias PatzoldAbstract:In this paper, we study the performance of hybrid automatic repeat request (HARQ) with Incremental Redundancy over double Rayleigh channels, a common model for the fading amplitude of vehicle-to-vehicle communication systems. We inves- tigate the performance of HARQ from an information theoretic perspective. Analytical expressions are derived for the -outage capacity, the average number of transmissions, and the average transmission rate of HARQ with Incremental Redundancy assum- ing a maximum number of HARQ rounds. Moreover, we evaluate the delay experienced by Poisson arriving packets for HARQ with Incremental Redundancy. We provide analytical expressions for the expected waiting time, the packet's sojourn time in the queue, the average consumed power, and the energy efficiency. In our study, the communication rate per HARQ round is adjusted to the average signal-to-noise ratio (SNR) such that a target outage prob- ability is not exceeded. This setting conforms with communication systems in which a quality of service is expected regardless of the channel conditions. Our analysis underscores the importance of HARQ in improving the spectral efficiency and reliability of communication systems. We demonstrate as well that the explored HARQ scheme achieves full diversity. Additionally, we investigate the tradeoff between energy efficiency and spectral efficiency. Index Terms—Hybrid automatic repeat request (HARQ), incre- mental Redundancy, energy efficiency, delay analysis, information outage capacity, average transmission rate, average number of transmissions.
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on the performance analysis of hybrid arq with Incremental Redundancy and with code combining over free space optical channels with pointing errors
IEEE Photonics Journal, 2014Co-Authors: Emna Zedini, Ali Chelli, Mohamedslim AlouiniAbstract:In this paper, we investigate the performance of hybrid automatic repeat request (HARQ) with Incremental Redundancy (IR) and with code combining (CC) from an information-theoretic perspective over a point-to-point free-space optical (FSO) system. First, we introduce new closed-form expressions for the probability density function, the cumulative distribution function, the moment generating function, and the moments of an FSO link modeled by the Gamma fading channel subject to pointing errors and using intensity modulation with direct detection technique at the receiver. Based on these formulas, we derive exact results for the average bit error rate and the capacity in terms of Meijer's G functions. Moreover, we present asymptotic expressions by utilizing the Meijer's G function expansion and using the moments method, too, for the ergodic capacity approximations. Then, we provide novel analytical expressions for the outage probability, the average number of transmissions, and the average transmission rate for HARQ with IR, assuming a maximum number of rounds for the HARQ protocol. Besides, we offer asymptotic expressions for these results in terms of simple elementary functions. Additionally, we compare the performance of HARQ with IR and HARQ with CC. Our analysis demonstrates that HARQ with IR outperforms HARQ with CC.
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performance analysis of hybrid arq with Incremental Redundancy over amplify and forward dual hop relay channels
arXiv: Information Theory, 2014Co-Authors: Ali Chelli, Amir Hadjtaieb, Mohamedslim AlouiniAbstract:In this paper, we consider a three node relay network comprising a source, a relay, and a destination. The source transmits the message to the destination using hybrid automatic repeat request (HARQ) with Incremental Redundancy (IR). The relay overhears the transmitted message, amplifies it using a variable gain amplifier, and then forwards the message to the destination. This latter combines both the source and the relay message and tries to decode the information. In case of decoding failure, the destination sends a negative acknowledgement. A new replica of the message containing new parity bits is then transmitted in the subsequent HARQ round. This process continues until successful decoding occurs at the destination or a maximum number $M$ of rounds is reached. We study the performance of HARQ-IR over the considered relay channel from an information theoretic perspective. We derive exact expressions and bounds for the information outage probability, the average number of transmissions, and the average transmission rate. Moreover, we evaluate the delay experienced by Poisson arriving packets over the considered relay network. We also provide analytical expressions for the expected waiting time, the sojourn time, and the energy efficiency. The derived exact expressions are validated by Monte Carlo simulations.
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on the performance of hybrid arq with Incremental Redundancy and with code combining over relay channels
IEEE Transactions on Wireless Communications, 2013Co-Authors: Ali Chelli, Mohamedslim AlouiniAbstract:In this paper, we consider a relay network consisting of a source, a relay, and a destination. The source transmits a message to the destination using hybrid automatic repeat request (HARQ). The relay overhears the transmitted messages over the different HARQ rounds and tries to decode the data packet. In case of successful decoding at the relay, both the relay and the source cooperate to transmit the message to the destination. The channel realizations are independent for different HARQ rounds. We assume that the transmitter has no channel state information (CSI). Under such conditions, power and rate adaptation are not possible. To overcome this problem, HARQ allows the implicit adaptation of the transmission rate to the channel conditions by the use of feedback. There are two major HARQ techniques, namely HARQ with Incremental Redundancy (IR) and HARQ with code combining (CC). We investigate the performance of HARQ-IR and HARQ-CC over a relay channel from an information theoretic perspective. Analytical expressions are derived for the information outage probability, the average number of transmissions, and the average transmission rate. We illustrate through our investigation the benefit of relaying. We also compare the performance of HARQ-IR and HARQ-CC and show that HARQ-IR outperforms HARQ-CC.
Giuseppe Caire - One of the best experts on this subject based on the ideXlab platform.
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Incremental Redundancy hybrid arq schemes based on low density parity check codes
IEEE Transactions on Communications, 2004Co-Authors: S Sesia, Giuseppe Caire, G VivierAbstract:We study the throughput of hybrid automatic retransmission request (H-ARQ) schemes based on Incremental Redundancy (IR) over a block-fading channel. We provide an information-theoretic analysis assuming binary random coding and typical-set decoding. Then, we study the performance of low-density parity-check (LDPC) code ensembles with iterative belief-propagation decoding, and show that, under the hypothesis of infinite-length codes, LDPCs yield almost optimal performance. Unfortunately, standard finite-length LDPC ensembles incur a considerable performance loss with respect to their infinite-length counterpart, because of their poor frame-error rate (FER) performance. In order to recover part of this loss, we propose two simple yet effective methods: using a modified LDPC ensemble designed to improve the FER; and using an outer selective-repeat protocol acting on smaller packets of information bits. Surprisingly, these apparently very different methods yield almost the same performance gain and recover a considerable fraction of the optimal throughput, thus making practical finite-length LDPC codes very attractive for data wireless communications based on IR H-ARQ schemes.
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the performance of Incremental Redundancy schemes based on convolutional codes in the block fading gaussian collision channel
IEEE Transactions on Wireless Communications, 2004Co-Authors: C F Leanderson, Giuseppe CaireAbstract:The throughput performance of Incremental Redundancy (INR) schemes, based on short constraint length convolutional codes, is evaluated for the block-fading Gaussian collision channel. Results based on simulations and union bound computations are compared to estimates of the achievable throughput performance with random binary and Gaussian coding in the limit of large block lengths, obtained through information outage considerations. For low channel loads, it is observed that INR schemes with binary convolutional codes and limited block length may provide throughput close to the achievable performance for binary random coding. However, for these low loads, compared to binary random coding, Gaussian random coding may provide significantly better throughput performance, which prompts the use of larger modulation constellations. For high channel loads, a relatively large gap in throughput performance between binary convolutional codes and binary random codes indicates a potential for extensive performance improvement by alternative coding strategies. Only small improvements of the throughput have been observed by increasing the complexity through increased state convolutional coding.
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the throughput of an ldpc based Incremental Redundancy scheme over block fading channels
Information Theory Workshop, 2002Co-Authors: S Sesia, Giuseppe CaireAbstract:Incremental-Redundancy (INR) is a form of hybrid ARQ where the receiver asks the transmitter for additional parity bits when decoding is not successful. This technique is particularly useful in time-selective fading channels, since it implements variable-rate adaptive transmission with a very simple feedback binary channel, where the feedback messages are positive or negative acknowledgments (ACK and NACK, respectively). In this work an information-theoretic analysis of the achievable throughput and delay of INR over block-fading channels for random binary codes and for low-density parity-check (LDPC) binary linear codes.
Richard D. Wesel - One of the best experts on this subject based on the ideXlab platform.
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Variable-Length Coding With Shared Incremental Redundancy: Design Methods and Examples
IEEE Transactions on Communications, 2019Co-Authors: Haobo Wang, Sudarsan V. S. Ranganathan, Richard D. WeselAbstract:Variable-length (VL) coding with feedback is a commonly used technique that can approach point-to-point Shannon channel capacity with a significantly shorter average codeword length than fixed-length coding without feedback. This paper uses the inter-frame coding of Zeineddine and Mansour, originally introduced to address varying channel-state conditions in broadcast wireless communication, to approach capacity on point-to-point channels using VL codes without feedback. The per-symbol complexity is comparable to decoding the VL code with feedback (plus the additional complexity of a small peeling decoder amortized over many VL codes) and presents the opportunity for encoders and decoders that utilize massive parallel processing, where each VL decoder can process simultaneously. This paper provides an analytical framework and a design process for the degree distribution of the inter-frame code that allows the feedback-free system to achieve 96% or more of the throughput of the original VL code with feedback. As examples of VL codes, we consider non-binary (NB) low-density parity-check (LDPC), binary LDPC, and convolutional VL codes. The NB-LDPC VL code with an 8-bit CRC and an average codeword length of 336 bits achieves 85% of capacity with four rounds of ACK/NACK feedback. The proposed scheme using shared Incremental Redundancy without feedback achieves 97% of that performance or 83% of the channel capacity.
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a systematic approach to Incremental Redundancy over erasure channels
International Symposium on Information Theory, 2018Co-Authors: Anoosheh Heidarzadeh, Jeanfrancois Chamberland, Parimal Parag, Richard D. WeselAbstract:As sensing and instrumentation play an increasingly important role in systems controlled over wired and wireless networks, the need to better understand delay-sensitive communication becomes a prime issue. Along these lines, this article studies the operation of data links that employ Incremental Redundancy as a practical means to protect information from the effects of unreliable channels. Specifically, this work extends a powerful methodology termed sequential differential optimization to choose near-optimal block sizes for hybrid ARQ over erasure channels. Furthermore, results show that the impact of the coding strategy adopted and the propensity of the channel to erase symbols naturally decouple when analyzing throughput. Overall, block size selection is motivated by normal approximations on the probability of decoding success at every stage of the Incremental transmission process. This novel perspective, which rigorously bridges hybrid ARQ and coding, offers a pragmatic means to select code rates and blocklengths for Incremental Redundancy.
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a systematic approach to Incremental Redundancy over erasure channels
arXiv: Information Theory, 2018Co-Authors: Anoosheh Heidarzadeh, Jeanfrancois Chamberland, Parimal Parag, Richard D. WeselAbstract:As sensing and instrumentation play an increasingly important role in systems controlled over wired and wireless networks, the need to better understand delay-sensitive communication becomes a prime issue. Along these lines, this article studies the operation of data links that employ Incremental Redundancy as a practical means to protect information from the effects of unreliable channels. Specifically, this work extends a powerful methodology termed sequential differential optimization to choose near-optimal block sizes for hybrid ARQ over erasure channels. In doing so, an interesting connection between random coding and well-known constants in number theory is established. Furthermore, results show that the impact of the coding strategy adopted and the propensity of the channel to erase symbols naturally decouple when analyzing throughput. Overall, block size selection is motivated by normal approximations on the probability of decoding success at every stage of the Incremental transmission process. This novel perspective, which rigorously bridges hybrid ARQ and coding, offers a pragmatic means to select code rates and blocklengths for Incremental Redundancy.
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approaching capacity using Incremental Redundancy without feedback
International Symposium on Information Theory, 2017Co-Authors: Haobo Wang, Sudarsan V. S. Ranganathan, Richard D. WeselAbstract:Variable-length codes with Incremental Redundancy controlled by feedback allow a system to approach capacity with short average blocklengths and thus relatively low-complexity decoders. This paper shows how to use those same variable-length codes with Incremental Redundancy to approach capacity without feedback. The general principle is to provide a common pool of Redundancy that can be accessed by exactly the variable-length codes that need it. We provide example implementations using both regular and irregular low-density generator matrix (LDGM) codes to provide this common pool of Redundancy, utilizing the inter-frame coding approach that Zeineddine and Mansour used to combat rate variation due to fading in broadcast transmissions. Obtaining the LDGM degree distributions requires a new design methodology involving differential evolution for a generalized peeling decoder. Monte-Carlo simulations using a 2dB binary-input additive white Gaussian noise channel confirm the feasibility of this new approach. For a frame error rate of 10−3, the irregular LDGM code achieves 96% of the throughput of the corresponding feedback system.
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an information density approach to analyzing and optimizing Incremental Redundancy with feedback
International Symposium on Information Theory, 2017Co-Authors: Haobo Wang, Sudarsan V. S. Ranganathan, Nathan D Wong, Alexander M Baldauf, Christopher K Bachelor, Dariush Divsalar, Richard D. WeselAbstract:This paper uses a case study of a tail-biting convolutional code (with successful decoding indicated by the reliability output Viterbi algorithm) to present an information density approach for analyzing and optimizing the throughput of systems using Incremental Redundancy controlled by feedback. Polyan-skiy's normal approximation combined with a linear model for the information gap of a rate-compatible code family provides a simple and accurate characterization of the behavior of feedback systems employing practical codes, such as convolutional or low-density parity-check codes. Especially for short message lengths on the order of k < 50 message bits, the newly proposed model is more accurate than Vakilinia's model in which the rate of first successful decoding has a Gaussian probability density function.
