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TABLE BASED DEcoding OF RATE ONE-HALF convolutional-CODES

IEEE TRANSACTIONS ON COMMUNICATIONS 1995年第2-4期43卷 681-686页

作者： DHOLAKIA, A VOUK, MA BITZER, DL Department of Computer Science North Carolina State University Raleigh NC USA

Table based error correction and decoding of rate one-half convolutional codes is described. A new class of fast-decodeable locally invertible convolutional coder based on a one-to-one mapping between information and encoded blocks of equal lengths is defined. The syndrome is used as an address to access a correction table which stores precomputed correction information, The correction table gen generation process is described and a specific table based correction algorithm is given. Performance of this scheme is analyzed and simulation results are presented.

关键词： correction algorithm error correction convolutional coding New classes DEcoding Syndromes based correction table

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FINITE-STATE CODES

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IEEE TRANSACTIONS ON INFORMATION THEORY 1988年第5期34卷 1083-1089页

作者： POLLARA, F MCELIECE, RJ ABDELGHAFFAR, K CALTECH DEPT ELECT ENGNPASADENACA 91125

A class of codes called finite-state (FS) codes is defined and investigated. The codes, which generalize both block and convolutional codes, are defined by their encoders, which are finite-state machines with parallel inputs and outputs. A family of upper bounds on the free distance of a given FS code is derived. A general construction for FS codes is given, and it is shown that in many cases the FS codes constructed in this way have a free distance that is the largest possible. Catastrophic error propagation (CEP) for FS codes is also discussed. It is found that to avoid CEP one must solve the graph-theoretic problem of finding a uniquely decodable edge labeling of the state diagram.

关键词： Codes ENCODER finite state machines Upper bound diagrams of states CEP convolutional coding

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convolutionalLY CODED FREQUENCY-HOPPING COMMUNICATIONS WITH NONIDEAL INTERLEAVING

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IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 1990年第5期8卷 823-836页

作者： LAUFER, S REICHMAN, A TEL AVIV UNIV DEPT ELECTR SYSTIL-69978 TEL AVIVISRAEL

The interleaving span of coded frequency-hopped (FH) systems is often constrained to be smaller than the decoder memory length, i.e. nonideal interleaving is performed. An upper bound on the performance of a Viterbi decoder of a convolutional code with nonideal interleaving is presented. A soft decision diversity combining technique is introduced, and the performance of combined convolutional and diversity coding subject to worst-case partial band noise jamming is investigated. Optimization of the FH system performance subject to constraints of allowed delay and synthesizer settling time provides the best combination of interleaving span and hopping rate. The FH system considered employs M-ary frequency-shift key (MFSK) modulation and noncoherent demodulation with 2-b soft decision based on Viterbi's ratio-threshold technique.

关键词： soft decision Viterbi decoders noncoherent demodulation Frequency hopping convolutional coding frequency shift keying

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Improved performance of coded digital FM

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IEEE TRANSACTIONS ON COMMUNICATIONS 1999年第11期47卷 1701-1708页

作者： Pawula, RF Univ Arizona Dept Math Tucson AZ 85721 USA

The performance of convolutionally encoded narrow-band digital FM with Viterbi decoding was considered in some detail by Simon [1] for a noncoherent limiter/discriminator (L/D) with integrate and dump (I&D) bit detection. Employing a new threshold receiver which averages the output of the I&D detector with the output of a sample and hold (S&H) detector, a 3-dB improvement over Simon's results for the bit error probability with FM clicks will be shown to be achievable. At low error rates, the performance of this new receiver is, moreover, comparable to that obtained when the clicks are exactly removed by Simon's hypothetical 'genie."

关键词： convolutional coding digital FM

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Concatenated convolutional and differential codes in interference-suppressed DS-CDMA systems

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IEE PROCEEDINGS-COMMUNICATIONS 2002年第2期149卷 99-104页

作者： Li, Y Li, KH Natl Univ Singapore Ctr Wireless Commun Singapore 117674 Singapore Nanyang Technol Univ Sch Elect & Elect Engn Singapore 639798 Singapore

A serial concatenated convolutional and differential coding scheme is employed in a multi-user direct-sequence code-division multiple-access (DS-CDMA) system. The system consists of single-user detectors (SUDs), which are used to suppress multiple-access interference (MAI) with no requirement of other users' spreading codes, timing, or phase information. The differential code, treated as a convolutional code of code rate I and memory 1, does not sacrifice the coding efficiency and has the least number of states. The iterative process exchanges information between the differential decoder and the convolutional decoder. Both component decoders adopt the a posteriori probability (APP) algorithm. Numerical results in additive white Gaussian noise (AWGN) channels show that this concatenated coding scheme provides better performance and more flexibility than conventional convolutional codes in DS-CDMA systems, even in the sense of similar complexity. Further study shows that the performance of this coding scheme applied to DS-CDMA systems with SUDs improves by increasing the processing gain or the number of taps of the interference suppression filter. and degrades for higher near-far interfering power or additional near-far interfering users.

关键词： Direct-sequence code-division multiple access Rejection filters AWGN Codes code rate CDMA mobile communications decoders labeling scheme WATER FAUCETS Iterative Process convolutional coding differential coding

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Error probability performance for W-CDMA systems with multiple transmit and receive antennas in correlated Nakagami fading channels

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2002年第6期51卷 1502-1516页

作者： Luo, JX Zeidler, JR Proakis, JG Univ Calif San Diego Dept Elect & Comp Engn La Jolla CA 92093 USA Space & Naval Warfare Syst Ctr San Diego CA 92152 USA Northeastern Univ Dept Elect & Comp Engn Boston MA 02115 USA

The bit error rate (BER) performance of a two-dimensional (2-D) RAKE receiver, in combination with transmit diversity on the downlink of a wide-band CDMA (W-CDMA) system, is presented. The analyses assume correlated fading between receive antenna array elements, and an arbitrary number of independent but nonidentical resolvable multipaths combined by the RAKE receiver in the general Nakagami-m fading channel framework. The impact of the array configuration (e.g., the number of transmit antennas and receive antennas, the antenna element separation) and the operating environment parameters (such as the fading severity, angular spread and path delay profile) on the overall space-path diversity gain can be directly evaluated. In addition, the exact pairwise error probability of a convolutional coded system is obtained, and the coding gain of a space-path diversity receiver is quantified.

关键词： convolutional coding correlated Nakagami fading multiple-input-multiple-output (MIMO) systems pairwise error probability space-path diversity two-dimensional (2-D) RAKE receiver

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FORWARD ERROR CORRECTION FOR AN ATMOSPHERIC NOISE CHANNEL

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IEEE TRANSACTIONS ON COMMUNICATIONS 1992年第5期40卷 863-872页

作者： OLSON, KE ENGE, PK WORCESTER POLYTECH INST DEPT ELECT ENGNWORCESTERMA 01609

Atmospheric noise is caused by lightning and dominates other natural radio noise sources below 30 MHz. A wide-band atmospheric noise process appears as low-power Gaussian background process with bursts of high-power impulses. The impulses are due to nearby lightning and cause the first-order density of atmospheric noise to have longer tails than the Gaussian distribution. They also tend to occur in groups which means that the atmospheric noise channel has memory. Digital radio systems which operate on the atmospheric noise channel can use hard decisions to desensitize the receiver to the bursts, and forward error correction to recover those symbols which are received incorrectly. If these systems use a high degree of interleaving, then the channel can be modelled as a binary symmetric channel. However, many radio systems which operate below 30 MHz must minimize data delay and therefore interleaving depth must be chosen carefully. This paper uses two Markov chains to model the memory of the atmospheric noise channel. It derives the transition probabilities for these chains from atmospheric noise error processes which were recorded at 306 kHz. Then, it uses the models to estimate the probability of codeword error, and compares these estimates to codeword error rates which are obtained directly from the recorded error processes. These comparisons are made for the Golay code with a variety of bit interleaving depths, and for a Reed-Solomon code with a variety of symbol interleaving depths. Both Markov channel models predict the actual performance of the codes with much greater accuracy than the binary symmetric channel. This paper also includes some results for binary convolutional codes.

关键词： Forward error correction PERFORMANCE CODES Reed-Solomon codes error correction codeword atmospherics Golay codes convolutional coding TRANSITION PROBABILITIES

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ON THE PERFORMANCE OF RATE 1/2 convolutional-CODES WITH QPSK ON RICIAN FADING CHANNELS

引用

IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 1990年第2期39卷 161-170页

作者： CHEN, YL WEI, CH Institute of Electronics National Chiao Tung University Hsinchu Taiwan

Consideration is given to the bit error probability performance of rate 1/2 convolutional codes in conjunction with quaternary phase shift keying (QPSK) modulation and maximum-likelihood Viterbi decoding on fully interleaved Rician fading channels. Applying the generating function union bounding approach, an asymptotically tight analytic upper bound on the bit error probability performance is developed under the assumption of using the Viterbi decoder with perfect fading amplitude measurement. Bit error probability performance of constraint length K=3-7 codes with QPSK is numerically evaluated using the developed bound. Tightness of the bound is examined by means of computer simulation. The influence of perfect amplitude measurement on the performance of the Viterbi decoder is observed. A performance comparison with rate 1/2 codes with binary phase shift keying (BPSK) is provided.

关键词： Viterbi decoders Binary phase shift keying Quadrature phase shift keying bit error probability convolutional coding Computer Simulation Rician fading channels Performance appraisal

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Serial Turbo Codes with a Low Complexity of Reception Algorithms

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JOURNAL OF COMMUNICATIONS TECHNOLOGY AND ELECTRONICS 2010年第10期55卷 1115-1121页

作者： Nazarov, L. E. Golovkin, I. V.

The results of investigating the developed efficient procedures of iterative reception of serial turbo codes based on a simple convolutional code with two possible states of a code trellis are presented.

关键词： reception Serial Publications BISTABILITY convolutional coding turbo codes

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On the design and selection of convolutional codes for an uninterleaved, bursty Rician channel

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IEEE TRANSACTIONS ON COMMUNICATIONS 1995年第12期43卷 2914-2921页

作者： Kaplan, G Shamai, S Kofman, Y TECHNION ISRAEL INST TECHNOL DEPT ELECT ENGN IL-32000 HAIFA ISRAEL

This work focuses on code design and code selection rules under power and decoding delay constraints for an antipodal (BPSK) modulated and convolutionally encoded communication system. The system operates over a slowly fading AWGN channel, described here by the block-fading model. We specialize to perfect coherent detection with maximum likelihood decoding assuming ideal channel information (the instantaneous fading values). The dominant design criterion in this scenario is the code diversity level in terms of blocks while the standard Hamming distance plays a secondary role. A code design procedure, based on maximum distance separable (MDS) cyclic block codes is presented along with a code-search algorithm. The performance results of selected codes are assessed via simulation and compared to those achieved by Reed-Solomon codes with erasure and error decoding.

关键词： Block codes maximum likelihood decoding DEcoding Codes design and selection Rician channels code selection Hamming distance AWGN channels convolutional coding fading color coherence information channels

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