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TURBO CODES: a tutorial on a new class of powerful error correcting coding schemes - Part II: Decoder Design and Performance
, 1998
"... This is a tutorial paper meant to introduce the reader to the new concept of turbo codes. This is a new and very powerful error correction technique which outperforms all previous known coding schemes. It can be used in any communication system where a significant power saving is required or the ope ..."
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Cited by 13 (0 self)
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This is a tutorial paper meant to introduce the reader to the new concept of turbo codes. This is a new and very powerful error correction technique which outperforms all previous known coding schemes. It can be used in any communication system where a significant power saving is required or the operating signal--to--noise ratio (SNR) is very low. Deep space communications, mobile satellite/cellular communications, microwave links, paging, etc., are some of the possible applications of this revolutionary coding technique. Part I of the paper discussed the history of turbo codes, why they are different from traditional convolutional/block codes, the turbo encoder structures and issues related to the interleaver design. Part II addresses the decoder architecture, the achievable performance for turbo codes for a wide range of coding rates and modulation techniques and discusses delay and implementation issues. 2 1 Introduction The optimum decoding of turbo codes is the maximum likeli...
Bandwidth Efficient Turbo Coding For High Speed Mobile Satellite Communications
- in Proc. Int. Symp. on Turbo Codes and Related Topics
, 1997
"... This paper describes an application of turbo codes in conjunction with 16QAM in high speed mobile satellite communications. The channel characteristics, the architecture of the modem and the performance curves for the selected turbo codes are presented. 1 INTRODUCTION The Institute for Telecommunic ..."
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Cited by 12 (2 self)
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This paper describes an application of turbo codes in conjunction with 16QAM in high speed mobile satellite communications. The channel characteristics, the architecture of the modem and the performance curves for the selected turbo codes are presented. 1 INTRODUCTION The Institute for Telecommunications Research (ITR) from the University of South Australia investigated suitable modulation and error correction schemes for 2 bit/symbol bandwidth efficiency. A feasibility study was done for data rates between 4.8 kbit/s and 128 kbit/s. Rate half turbo codes obtained from puncturing a rate third turbo code [1, 2] and Gray mapping into a 16 Quadrature Amplitude Modulation (16QAM) scheme [3] is the preferred solution and some of the results are presented in this paper. Following the feasibility study, a proof of concept study which includes building a modem/codec is under way. This will allow optimisation of system parameters and the performance of field trials. The most important factors ...
Unit-memory Hamming turbo codes
- Proceedings of IEEE International Symposium on Information Theory '95
, 1995
"... Several parallel concatenated coding schemes (turbo codes) based on multi-memory (MM) convolutional codes (more specifically, a (2,1,4,7) code) were recently proposed to achieve near Shannon-limit error correction performance with ..."
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Cited by 10 (5 self)
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Several parallel concatenated coding schemes (turbo codes) based on multi-memory (MM) convolutional codes (more specifically, a (2,1,4,7) code) were recently proposed to achieve near Shannon-limit error correction performance with
Scalable image and video transmission using irregular repeat–accumulate codes with fast algorithm for optimal unequal error protection
- IEEE Trans. Commun
, 2004
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Reduced-complexity approach to iterative detection of SOQPSK
- IEEE TRANS. COMMUN
, 2007
"... We develop a reduced-complexity approach for the detection of coded shaped-offset quadrature phase-shift keying (SOQPSK), a highly bandwidth-efficient and popular constantenvelope modulation. The complexity savings result from viewing the signal as a continuous-phase modulation (CPM). We give a sim ..."
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Cited by 9 (3 self)
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We develop a reduced-complexity approach for the detection of coded shaped-offset quadrature phase-shift keying (SOQPSK), a highly bandwidth-efficient and popular constantenvelope modulation. The complexity savings result from viewing the signal as a continuous-phase modulation (CPM). We give a simple and convenient closed-form expression for a recursive binaryto-ternary precoder for SOQPSK. The recursive nature of this formulation is necessary in serially concatenated systems where SOQPSK serves as the inner code. We show that the proposed detectors are optimal in the full-response case, and are near-optimal in the partial-response case due to some additional complexity reducing approximations. In all cases, the proposed detectors achieve large coding gains for serially concatenated coded SOQPSK. These gains are similar to those reported recently by Li and Simon, which were obtained using a more complicated cross-correlated trelliscoded quadrature modulation (XTCQM) interpretation.
Permutation Polynomial Interleavers: An Algebraic-Geometric Perspective
, 2006
"... An interleaver is a critical component for the channel coding performance of turbo codes. Algebraic constructions are important because they admit analytical designs and simple, practical hardware implementation. The spread factor of an interleaver is a common measure for turbo coding applications. ..."
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Cited by 8 (1 self)
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An interleaver is a critical component for the channel coding performance of turbo codes. Algebraic constructions are important because they admit analytical designs and simple, practical hardware implementation. The spread factor of an interleaver is a common measure for turbo coding applications. Maximum-spread interleavers are interleavers whose spread factors achieve the upper bound. An infinite sequence of quadratic permutation polynomials over integer rings that generate maximum-spread interleavers is presented. New properties of permutation polynomial interleavers are investigated from an algebraic-geometric perspective resulting in a new non-linearity metric for interleavers. A new interleaver metric that is a function of both the non-linearity metric and the spread factor is proposed. It is numerically demonstrated that the spread factor has a diminishing importance with the block length. A table of good interleavers for a variety of interleaver lengths according to the new metric is listed. Extensive computer simulation results with impressive frame error rates confirm the efficacy of the new metric. Further, when tail-biting constituent codes are used, the resulting turbo codes are quasi-cyclic.
Optimal Scheduling for Multiple Serially Concatenated Codes
- in Proc. Int. Symp. on Turbo Codes and Rel. Topics
, 2003
"... In this paper an algorithm is proposed that finds the optimal activation schedule for the component decoders for iterative decoding of systems with three or more serially concatenated codes. It is optimal in terms of minimizing the total decoding complexity required to reach the convergence point. I ..."
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Cited by 8 (1 self)
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In this paper an algorithm is proposed that finds the optimal activation schedule for the component decoders for iterative decoding of systems with three or more serially concatenated codes. It is optimal in terms of minimizing the total decoding complexity required to reach the convergence point. It is also demonstrated that the convergence threshold can be found by combining several three-dimensional extrinsic information transfer (EXIT) surfaces into one two-dimensional EXIT chart.
Multiple parallel concatenated codes with optimal puncturing and energy distribution
- in Proc. IEEE Int. Conf. Commun.(ICC ’05), Seoul, Korea
, 2005
"... Abstract — In this paper we show how to find optimal energy distribution together with optimal puncturing ratios for parallel concatenated codes with two or more constituent codes. The energy distribution and the puncturing ratios are optimal in terms of minimizing the average signal-to-noise ratio ..."
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Cited by 7 (5 self)
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Abstract — In this paper we show how to find optimal energy distribution together with optimal puncturing ratios for parallel concatenated codes with two or more constituent codes. The energy distribution and the puncturing ratios are optimal in terms of minimizing the average signal-to-noise ratio convergence threshold. The extrinsic information transfer functions of the constituent codes are used for the optimization. Using this technique we obtain additional degrees of freedom for constructing codes with low convergence thresholds over a large range of code rates. I.
Interleaver properties and their applications to the trellis complexity analysis of turbo codes
, 2001
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Using the Mean Reliability as a Design and Stopping Criterion for Turbo Codes
, 2001
"... By means of the mean reliability (defined as the mean of the absolute values of loglikelihood ratios), a new design of parallel concatenated "turbo" codes is proposed. This criterion allows us to describe the behavior of the constituent decoders and, furthermore, to predict the behavior of ..."
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Cited by 6 (2 self)
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By means of the mean reliability (defined as the mean of the absolute values of loglikelihood ratios), a new design of parallel concatenated "turbo" codes is proposed. This criterion allows us to describe the behavior of the constituent decoders and, furthermore, to predict the behavior of the iterative decoder for large block lengths. The mean reliability can also be used as a stopping criterion.
