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A DIVERSITY COMBINING DS/CDMA SYSTEM WITH convolutional ENcoding AND VITERBI DEcoding

IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 1995年第2期44卷 304-312页

作者： SOUISSI, S WICKER, SB GEORGIA INST TECHNOL SCH ELECT & COMP ENGNCODING & INFORMAT THEORY LABATLANTAGA 30332

Averaged diversity combining is applied to an asynchronous DS/CDMA system using convolutional encoding and Viterbi decoding, A CRC code is included in the scheme to trigger retransmission requests, Multiple received packets are combined on a bit by bit basis to form a single, more reliable packet, The error correcting decoder operates on the combined packet, as opposed to the most recently received individual packet (e.g., as in a type-I hybrid ARQ protocol), substantially increasing the probability of acceptance with each additional transmission, We show that the proposed technique allows a significant increase in the CDMA system capacity, throughput, and reliability.

关键词： ACCEPTANCE Packet Cyclic redundancy check convolutional coding Binary digits RETRANSMISSION Viterbi decoding diversity reception

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A personal history of the Viterbi algorithm

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IEEE SIGNAL PROCESSING MAGAZINE 2006年第4期23卷 120-+页

作者： Viterbi, Andrew J. Universidad Carlos III de Madrid MADRID Spain

This paper describes how Andrew J. Viterbi developed a non-sequential decoding algorithm which proved useful in showing the superiority of convolutional codes over block codes for a given degree of decoding complexity. The Viterbi algorithm is now used in most digital cellular phones and digital satellite receivers as well as in such diverse fields as magnetic recoding, voice recognition, and DNA sequence analysis.

关键词： Viterbi decoding block codes computational complexity convolutional codes history Viterbi algorithm decoding complexity nonsequential decoding algorithm Social history convolutional coding complexity classes Viterbi algorithm digital cellular phone Block codes digital satellite receiver Viterbi decoding

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COMBINED CODED MULTI-H CPFSK SIGNALING

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IEEE TRANSACTIONS ON COMMUNICATIONS 1990年第10期38卷 1708-1715页

作者： FONSEKA, JP DAVIS, GR ARIZONA STATE UNIV DEPT ELECT ENGNTEMPEAZ 85287

A continuous-phase frequency-shift-keying (CPFSK) signaling technique is suggested that combines convolutional encoding and multi-h signaling. In contrast to regular multi-h signaling, this technique changes the modulation index in a preselected pattern in order to maximize the minimum Euclidean distance. A rate-1/2 convolutional encoder along with a 2-h quaternary CPFSK modulator which uses two fixed modulation indexes is considered. Minimum Euclidean distances are calculated corresponding to the best encoder/mapper combinations for different modulation index patterns at attractive pairs of modulation indexes. Numerical results obtained for encoder memory lengths of one and two are used to illustrate that the minimum Euclidean distance of coded CPFSK signals can be significantly increased by combining with multi-h signaling. Modulation index patterns which perform significantly better than regular multi-h signals are determined. An error event analysis over the additive-white-Gaussian noise channel is carried out to investigate the actual error rate performance and to verify the theoretical results.

关键词： Euclidean distance convolutional coding frequency shift keying

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A co-channel interference cancellation technique using orthogonal convolutional codes on multipath Rayleigh fading channel

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 1997年第1期46卷 114-128页

作者： Sanada, Y Wang, Q UNIV VICTORIA DEPT ELECT & COMP ENGN VICTORIA BC V8W 3P6 CANADA

This paper proposes and evaluates a new co-channel interference cancellation technique that utilizes orthogonal convolutional codes on a multipath Rayleigh fading channel, In a spread spectrum multiple access environment, co-channel interference (CCI) limits the performance of the communication link, To remove this interference, several CCI cancellation techniques have been proposed, including the technique that does not require the receiver to have knowledge of the cross-correlation between user sequences, This method leaves residual interference after the cancellation caused by errors in the initial decisions, To reduce the residual interference and improve the initial decisions, the proposed scheme utilizes the error-correcting capability of orthogonal convolutional codes, This paper evaluates the performance of this scheme, Our results show that the proposed CCI canceller offers all improvement in capacity by a factor of 1.5 similar to 3 as compared with a conventional canceller on a multipath Rayleigh fading channel, The proposed canceller works in the presence of residual interference due to imperfect cancellation, The proposed canceller also has a capacity improvement with the use of soft handoff in a multicell configuration.

关键词： Raleigh fading channels Orthogonal Rayleigh fading soft handoff convolutional coding Cochannel interference CANCELLATIONS error correction capability

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Impact of code rate and constraint length variation on qualitative performance of OIDMA system with random inter-leaver

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OPTIK 2020年 202卷

作者： Maurya, Ajay Kumar Prakash, Ravi Sriwas, S. K. Kumar, Pramod Singh, R. K. Veer Bahadur Singh Purvanchal Univ Jaunpur UNS Inst Engn & Technol Dept Elect & Instrumentat Engn Jaunpur Uttar Predesh India Veer Bahadur Singh Purvanchal Univ UNS Inst Engn & Technol Dept Elect & Commun Engn Jaunpur 222003 Uttar Pradesh India Bundelkhand Inst Engn & Technol Dept Elect & Commun Engn Jhansi 284128 Uttar Pradesh India Manipal Acad Higher Educ Manipal Inst Technol Dept Elect & Commun Engn Manipal 576104 Karnataka India Kamla Nehru Inst Technol Sultanpur Dept Elect Engn Sultanpur 228118 Uttar Pradesh India

The impact of the code rate and constraint length on the qualitative performance of optical interleave division multiple access (OIDMA) system is analyzed. The various topologies of convolution encoder design have implemented by considering various shift registers as well as several Ex-OR gates to achieve the performance. Further, the bit error rate (BER) calculated for a different possible combination of random inter-leaver. The BER increases with the number of users, whereas it decreases with the code rate and constraint length.

关键词： OIDMA convolutional coding Network topology Random inter-leaver Constraint length

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Bahl-Cocke-Jelinek-Raviv decoding algorithm applied to the three-user binary adder channel

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IET COMMUNICATIONS 2015年第7期9卷 897-902页

作者： Alcoforado, Maria de Lourdes M. G. Oliveira, Mariana C. C. da Rocha, Valdemar C., Jr. Univ Pernambuco UPE Commun Grp GCOM Telecommun Lab LABTEL BR-50750470 Recife PE Brazil Univ Fed Pernambuco Commun Res Grp CODEC Dept Elect & Syst BR-50740550 Recife PE Brazil

The Bahl-Cocke-Jelinek-Raviv (BCJR) algorithm is a well-known maximum a posteriori probability decoding algorithm which has been proposed earlier for point to point communication applications, employing block codes or convolutional codes and turbo codes. This study describes an application of the BCJR algorithm for decoding the output of a multiple-access channel called the noisy three-user binary adder channel, in the presence of additive white Gaussian noise. The computer simulation results are presented for the overall coding performance in terms of bit error rate against signal-to-noise ratio.

关键词： Multiple Access Channel Block codes AWGN COMMUNICATIONS APPLICATION adders Access Channels Worm gears Maximum a posteriori estimation a posteriori probability decoding algorithm Simulation results convolutional coding

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Improved space-time convolutional codes for quasi-static slow fading channels

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2002年第4期1卷 563-571页

作者： Yan, Q Blum, RS Lehigh Univ Signal Proc & Commun Res Lab Bethlehem PA 18015 USA Lehigh Univ Dept Elect Engn & Comp Sci Bethlehem PA 18015 USA

Space-time convolutional codes, that provide maximum diversity and coding gain, are produced for cases with PSK modulation and various numbers of states and antennas. The codes are found using a new approach introduced recently in a companion paper. The new approach provides an efficient method that allows a search for optimum codes for many practical problems. The new approach also provides a simple method for augmenting the criteria of maximum diversity and coding gain with a new measure which is shown to be extremely useful for evaluating code performance without extensive simulations. To validate the approach, an extensive set of simulation results are presented comparing the codes designed here to many other recently proposed space-time convolutional codes. The comparisons, given in terms of frame error rate (FER), indicate that our new method provides codes which yield excellent performance. The approach is especially useful for finding a handful of good codes. Selection among these codes can be made with a limited number of simulations for FER.

关键词： convolutional coding space-time coding space-time modulation transmit diversity

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A multiuser interference cancellation technique utilizing convolutional codes and orthogonal multicarrier modulation for wireless indoor communications

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IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 1996年第8期14卷 1500-1509页

作者： Sanada, Y Nakagawa, M Department of Electrical Engineering Science and Technology Keio University Yokohama Japan

This paper suggests that multicarrier modulation reduces the complexity and the delay caused by the multiuser interference cancellation process utilizing convolutional codes. For spread spectrum multiple access, multiuser interference (interference due to signals from other users) limits the performance of the communication link. To remove this interference, a multiuser interference cancellation technique which utilizes orthogonal convolutional codes has been proposed for the uplink (mobiles to a base station) of the cellular code-division multiple-access (CDMA) systems. However, this technique requires the large interleavers and the huge memory, or the artificial multipath diversity and the RAKE system to achieve sufficient coding gain hit is applied for wireless indoor communications and fading is slow compared to the data rate. To reduce the complexity of the canceller, multicarrier modulation is employed as it provides frequency diversity gain and coding gain without the interleavers or the RAKE system. This paper shows that the multicarrier modulation reduces the complexity of the canceller and still provides sufficient coding gain in order to cancel the multiuser interference. The canceller with decoding in the initial decision and multicarrier modulation improves capacity by a factor of 1.4 as compared with the canceller without decoding.

关键词： fading color Cancellers rakes BASE STATION Complexity Multi-user Interference convolutional coding DEcoding coding gain indoor communication Pheromone a-Factor

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An artificial neural net Viterbi decoder

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IEEE TRANSACTIONS ON COMMUNICATIONS 1996年第2期44卷 165-171页

作者： Wang, XA Wicker, SB School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta GA USA

The Viterbi algorithm is a maximum likelihood means for decoding convolutional codes and has thus played an important role in applications ranging from satellite communications to cellular telephony, In the past, Viterbi decoders have usually been implemented using digital circuits. The speed of these digital decoders is directly related to the amount of parallelism in the design. As the constraint length of the code increases, parallelism becomes problematic due to the complexity of the decoder. In this paper an artificial neural network (ANN) Viterbi decoder is presented. The ANN decoder is significantly faster than comparable digital-only designs due to its fully parallel architecture. The fully parallel structure is obtained by implementing most of the Viterbi algorithm using analog neurons as opposed to digital circuits. Several modifications to the ANN decoder are considered, including an analog/digital hybrid design that results in an extremely fast and efficient decoder. The ANN decoder requires one-sixth the number of transistors required by the digital decoder. The connection weights of the ANN decoder are either +1 or -1, so weight considerations in the implementation are eliminated. This, together with the design's modularity and local connectivity, makes the ANN Viterbi decoder a natural fit for VLSI implementation. Simulation results are provided to show that the performance of the ANN decoder matches that of an ideal Viterbi decoder.

关键词： Viterbi algorithm decoders parallelism constraint length digital circuits Viterbi decoders convolutional coding Satellite communication

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Parameter optimization and simulated performance of a DVB-T digital television broadcasting system

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IEEE TRANSACTIONS ON BROADCASTING 1998年第1期44卷 131-138页

作者： Armada, AG Bardon, B Calvo, M Univ Politecn Madrid Grp Radiac Dpto SSR Madrid Spain

A prototype of a Digital Television Terrestrial Broadcasting System has been implemented according to the European DVB-T standard. The first step in the construction of this prototype involved parameter optimization via simulation. This paper presents the optimization process of the system parameters and the final achieved BER performance. Important design aspects such as interleaving, convolutional puncturing codes, Viterbi decoding, pilot-based channel correction and optimal pilot power are considered. The DVB-T standard offers some suggested values of the C/N ratio needed to achieve the desired BER requirements in the receiver. However, they have been obtained assuming ideal channel correction and synchronization. Simulation results are provided here in non-ideal conditions.

关键词： Viterbi decoding convolutional codes digital television error statistics optimisation television broadcasting television receivers television standards television transmitters video coding BER C/N ratio DVB-T digital television broadcasting system Europe television broadcasting Television Television receivers Digital television Parameter optimization pilot power Video coding Viterbi decoding terrestrial digital video broadcasting Broadcasting system convolutional coding television standards

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