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ERROR-PROBABILITY FOR REPEAT REQUEST SYSTEMS WITH convolutional-CODES

IEEE TRANSACTIONS ON INFORMATION THEORY 1993年第5期39卷 1680-1684页

作者： KUDRYASHOV, BD Department of Automatic Control Systems St. Petersburg Institute of Aviation Instrument Making Saint Petersburg Russia

A new decoding algorithm based on the modified Viterbi algorithm for repeat request systems is considered. A new asymptotic error probability bound is derived. It is shown that the error exponent for convolutional coding can be related to the exponent for block coding by a graphical method known as inverse concatenation construction.

关键词： REPEAT REQUEST SYSTEM convolutional coding VITERBI ALGORITHM ERROR PROBABILITY EXPONENT

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LIMITING ERROR PROPAGATION IN VITERBI DEcoding OF convolutional-CODES

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IEEE TRANSACTIONS ON INFORMATION THEORY 1989年第6期35卷 1295-1299页

作者： LEONARD, DA RODGER, CA Department of Algebra Combinatorics and Analysis Aubum University Auburn AL USA

The problem of avoiding infinite error propagation in noncatastrophic convolutional codes when using a truncated Viterbi decoder is considered. A truncation length tau is defined in terms of walks in the state diagram. The truncation length guarantees that, in the presence of a sufficiently long guard space, a truncated Viterbi decoder will always recover from any error event. This value of tau is the theoretically smallest possible truncation length.

关键词： Error propagation Viterbi decoders Cutoffs walking convolutional coding

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Pilot symbol assisted BPSK on Rayleigh fading channels with diversity:: Performance analysis and parameter optimization

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IEEE TRANSACTIONS ON COMMUNICATIONS 1998年第12期46卷 1560-1563页

作者： Schramm, P Müller, RR Univ Erlangen Nurnberg Telecommun Lab D-90411 Erlangen Germany

In this letter, the loss due to imperfect channel estimation is derived for pilot symbol assisted binary phase-shift keying (BPSK) on fading channels with diversity, The presented approach, which holds for both narrow-band and spread spectrum communication, further provides an analytical optimization of pilot symbol spacing. The loss due to channel estimation is demonstrated to be low if the maximum Doppler frequency is significantly less than the bit rate.

关键词： channel estimation code-division multiple access convolutional coding phase-shift keying Rayleigh fading channel spread spectrum

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QUANTIZATION LOSS IN convolutional DEcoding

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IEEE TRANSACTIONS ON COMMUNICATIONS 1993年第2期41卷 261-265页

作者： ONYSZCHUK, IM CHEUNG, KM COLLINS, O JOHNS HOPKINS UNIV DEPT ELECT ENGNBALTIMOREMD 21218 JET PROP LAB PASADENACA 91109

We study the loss in quantizing coded symbols from the AWGN channel with BPSK or QPSK modulation. A new quantization scheme and branch metric calculation method are presented. For the uniformly quantized AWGN channel, cutoff rate is used to determine the stepsize and the smallest number of quantization bits needed for a given bit signal-to-noise ratio (E(b)/N0) loss. A 9-level quantizer is presented, along with 3-bit branch metrics for a rate 1/2 code, which causes an E(b)/N0 loss of only 0.14 dB. These results also apply to soft-decision decoding of block codes. A tight upper bound is derived for the range of path metrics in a Viterbi decoder. The calculations are verified by simulations of several convolutional codes, including the new memory 14, rate 1/4 or 1/6 codes used by the big Viterbi decoders at JPL.

关键词： computational methods Quantization Viterbi decoders Binary phase shift keying step size Quadrature phase shift keying quadrature phase soft-decision decoding quantizer convolutional coding AWGN channels AWGN

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AN EFFICIENT MAXIMUM-LIKELIHOOD DEcoding ALGORITHM FOR GENERALIZED TAIL BITING convolutional-CODES INCLUDING QUASICYCLIC CODES

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IEEE TRANSACTIONS ON COMMUNICATIONS 1989年第8期37卷 875-879页

作者： WANG, Q BHARGAVA, VK Department of Electrical and Computer Engineering University of Victoria Victoria BC Canada

The complexity of the algorithm is shown to be asymptotically equal to that of the Viterbi algorithm and is very close for practical noisy channels. The latter is shown by means of computer simulation. The algorithm can be applied directly in an environment where soft-decision decoding is required or preferred. However, depending on the environment, some simplifications may be possible and/or necessary, resulting in suboptimal algorithms. Codes suitable for use with the algorithm should have short total memory length.

关键词： Environments maximum likelihood decoding soft-decision decoding maximum likelihood algorithms convolutional coding tail biting Viterbi algorithm Codes

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Improving RCPC Codes in Rate-Adaptive Optical Wireless Communications Systems

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WIRELESS PERSONAL COMMUNICATIONS 2013年第2期69卷 879-889页

作者： Maria Garrido-Balsells, Jose Jurado-Navas, Antonio Castillo-Vazquez, Miguel Puerta-Notario, Antonio Univ Malaga Dept Commun Engn E-29071 Malaga Spain

In this paper, we analyse the performance of rate-compatible punctured convolutional (RCPC) codes for wireless optical communications systems. For these environments, a novel hybrid RCPC coding scheme with a modified puncturing matrix is proposed based on the insertion of variable silence periods. This transmission technique achieves better bit-error rate results than conventional RCPC and convolutional coding schemes, in agreement to the obtained increase in the peak-to-average optical power ratio.

关键词： Optical communications Rate-compatible Punctured convolutional coding Variable silence periods Peak-to-average optical power ratio

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Robust transmission of Jpeg2000 images over noisy channels

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IEEE TRANSACTIONS ON CONSUMER ELECTRONICS 2002年第3期48卷 451-456页

作者： Sanchez, VS Mandal, MK Univ Alberta Edmonton AB Canada

An unequal channel protection technique for JPEG2000 encoded images is proposed The proposed technique takes advantage of the hierarchical organization of the JPEG2000 bit-stream and protects only the most important part of the compressed bit-stream, by means of a rate compatible punctured convolutional code. Both single-quality-layer and multiple-quality-layer compressions are considered The performance of this technique is evaluated under various noisy channel conditions. Simulation results show that the probability of correct decoding the received information and the quality of the reconstructed image are improved by the proposed technique.

关键词： image coding code standards telecommunication standards data compression visual communication noise telecommunication channels image reconstruction convolutional codes robust transmission JPEG2000 images noisy channels hierarchical organi JPEG code standards noisy channel image coding image reconstruction Data compression convolutional coding

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Integrated error control and power control for DS-CDMA multimedia wireless communications

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IEE PROCEEDINGS-COMMUNICATIONS 1999年第6期146卷 359-365页

作者： Zhuang, W Univ Waterloo Dept Elect & Comp Engn Waterloo ON N2L 3G1 Canada

The paper studies a packetised direct sequence code division multiple access (DS-CDMA) wireless network for providing multimedia services to mobile users. A strategy for integrating transmission error control with power control is presented and evaluated for the reverse link transmission where orthogonal signalling and noncoherent demodulation are necessary. For delay insensitive traffic requiring a very low bit error rate (BER), convolutional coding and an automatic retransmission request (ARQ) protocol are used to guarantee the transmission accuracy. By using the modified Viterbi decoder for decoding error detection, power control based on the received E-b/I-0 (the ratio of signal energy per bit to interference-and-noise density) is employed to minimise the total received power at the base station, resulting in a maximal frequency spectrum efficiency. Numerical results are presented to evaluate the optimal received E-b/I-0 value, the system radio frequency spectrum efficiency, and the optimal packet length, given the required BER and the traffic type. It is shown that the spectrum efficiency can be significantly increased by using an ARQ protocol with integrated optimal power control and convolutional coding for delay insensitive traffic.

关键词： packet radio networks power control total received power automatic retransmission request protocol telecommunication control bit error rate transmission accuracy Multiple access communication orthogonal signalling multimedia communication Multimedia communications base station modified Viterbi decoder DS-CDMA multimedia wireless communications Mobile radio systems automatic repeat request telecommunication signalling convolutional coding ARQ protocol reverse link transmission packetised direct sequence code division multiple access land mobile radio error control noncoherent demodulation error detection error statistics code division multiple access convolutional codes demodulation Viterbi decoding maximal frequency spectrum efficiency optimal packet length Protocols spread spectrum communication Codes radio spectrum management delay insensitive traffic radio frequency spectrum

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A MODEL FOR LOCAL MOBILE RADIO-COMMUNICATIONS WITH CORRECT PACKET CAPTURE

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IEEE TRANSACTIONS ON COMMUNICATIONS 1992年第4期40卷 847-854页

作者： ROBERTSON, RC HA, TT Department of Electrical and Computer Engineering Naval Postgraduate School Monterrey CA USA

An analysis of the performance of a local/mobile radio communications system utilizing the slotted ALOHA multiple random access protocol is presented in this paper. The probability of correct packet capture is evaluated for a local/mobile packet radio system using ideal coherent binary phase-shift keying (BPSK) modulation. Both the near/far effect and the effect of Rayleigh fading on the probability of correct packet capture are taken into account, but the effect of thermal noise is neglected since the interference due to competing packets is dominant in practical systems. The probability of correct packet reception is evaluated for a system using spatial diversity. In addition, the effect on system performance of either convolutional coding with hard decision Viterbi decoding or binary linear block coding with hard decision decoding is evaluated. The pseudo-Bayesian algorithm that has been developed to stabilize a packet system based on the slotted ALOHA protocol at maximum channel throughput is found to be adaptable to the local/mobile operating environment. For the slotted ALOHA system considered in this paper, it is possible to obtain channel throughputs as high as 0.66 provided a spatial diversity of around ten can be implemented.

关键词： Radiocommunication hard-decision decoding Slotted ALOHA Thermal noise Rayleigh fading Throughput spatial diversity Viterbi decoding System performance Packet convolutional coding

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A FAST ALGORITHM FOR COMPUTING DISTANCE SPECTRUM OF convolutional-CODES

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IEEE TRANSACTIONS ON INFORMATION THEORY 1989年第6期35卷 1146-1159页

作者： CEDERVALL, M JOHANNESSON, R Dept. of Inf. Theory Lund Univ. Sweden Department of Information Theory University of Lund Lund Sweden

A fast algorithm for searching a tree (FAST) is presented for computing the distance spectrum of convolutional codes. The distance profile of a code is used to limit substantially the error patterns that have to be searched. The algorithm can easily be modified to determine the number of nonzero information bits of an incorrect path as well as the length of an error event. For testing systematic codes, a faster version of the algorithm is given. FAST is much faster than the standard bidirectional search. On a microVAX, d/sub infinity /=27 was verified for a rate R=1/2, memory M=25 code in 37 s of CPU time. Extensive tables of rate R=1/2 encoders are given. Several of the listed encoders have distance spectra superior to those of any previously known codes of the same rate and memory. A conjecture than an R=1/2 systematic convolutional code of memory 2M will perform as well as a nonsystematic convolutional code of memory M is given strong support.

关键词： Spectra Fasting A* Algorithm Codes algorithms error model ENCODER CPU time GPR17 protein, human convolutional coding

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