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Adaptation in convolutionally Coded MIMO-OFDM Wireless Systems Through Supervised Learning and SNR Ordering

IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2010年第1期59卷 114-126页

作者： Daniels, Robert C. Caramanis, Constantine M. Heath, Robert W., Jr. Univ Texas Austin Dept Elect & Comp Engn Wireless Networking & Commun Grp Austin TX 78712 USA

Multiple-input-multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) wireless systems use link adaptation to exploit the dynamic nature of wireless environments. Link adaptation maximizes throughput while maintaining target reliability by adaptively selecting the modulation order and coding rate. Link adaptation is extremely challenging, however, due to the difficulty in predicting error rates in OFDM with binary convolutional codes, bit interleaving, MIMO processing, and real channel impairments. This paper proposes a new machine-learning framework that exploits past observations of the error rate and the associated channel-state information to predict the best modulation order and coding rate for new realizations of the channel state without modeling the input-output relationship of the wireless transceiver. Our approach is enabled through our new error-rate expression that is only parameterized by postprocessing signal-to-noise ratios (SNRs), ordered over subcarriers and spatial streams. Using ordered SNRs, we propose a low-dimensional feature set that enables machine learning to increase the accuracy of link adaptation. An IEEE 802.11n simulation study validates the application of this machine-learning framework in real channels and demonstrates the improved performance of SNR ordering as it compares with competing link-quality metrics.

关键词： Adaptive modulation and coding (AMC) convolutional coding IEEE 802.11n machine learning multiple-input multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) signal-to-noise ratio (SNR) ordering supervised learning

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A reduced-complexity online state sequence and parameter estimator for superimposed convolutional coded signals

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IEEE TRANSACTIONS ON COMMUNICATIONS 1997年第12期45卷 1565-1574页

作者： Brushe, GD Krishnamurthy, V White, LB UNIV MELBOURNE PARKVILLE VIC 3052 AUSTRALIA

This paper develops a reduced-complexity online state sequence and parameter estimator for superimposed convolutional coded signals, Joint state sequence and parameter estimation is achieved by iteratively estimating the state sequence via a variable reduced-complexity Viterbi algorithm (VRCVA) and the model parameters via a recursive expectation maximization (EM) approach, The VRCVA is developed from a fixed reduced-complexity Viterbi algorithm (FRCVA), The FRCVA is a special case of the delayed decision-feedback sequence estimation (DDFSE) algorithm, The performance of online versions of the FRCVA, VRCVA, and the standard Viterbi algorithm (VA) are compared when they are used to estimate the state sequence as part of the reduced-complexity online state sequence and parameter estimator.

关键词： convolutional coding maximum-likelihood estimation reduced complexity Viterbi decoding

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OPTIMAL SUBBLOCK-BY-SUBBLOCK DETECTION

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IEEE TRANSACTIONS ON COMMUNICATIONS 1995年第2-4期43卷 714-717页

作者： HOEHER, P Institute for Communications Technology German AeroSpace Research Establishment (DLR) Oberpfaffenhofen Germany

We propose a recursive algorithm to compute the joint maximum a-posteriori (MAP) probability of a subblock of N consecutive symbols (i.e., a sliding window of length N) of a finite-state discrete-time Markov process of length K greater than or equal to N observed in white noise given the whole block is received. This ''optimal subblock-by-subblock detector'' (OBBD, ''vector MAP'') is a generalization of the ''optimal symbol-by-symbol detector'' (OSSD, ''symbol-by-symbol MAP''), which is obtained for N = 1. The new algorithm improves applications with outer stage processing. This is indicated by investigating the average mutual information of a convolutional coding system. An example shows that the gain (in terms of average mutual information) by using joint probabilities could even exceed the gain by delivering soft OSSD outputs instead of hard outputs.

关键词： sliding windows Signs and symbols Finite Generalization Recursive algorithms Maximum a posteriori estimation white noise convolutional coding Joint Probability sub-block Gain Markov chain

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Dual convolutional codes and the MacWilliams identities

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PROBLEMS OF INFORMATION TRANSMISSION 2012年第1期48卷 21-30页

作者： Bocharova, I. E. Hug, F. Johannesson, R. Kudryashov, B. D. St Petersburg State Univ Informat Technol Mech & St Petersburg Russia Lund Univ S-22100 Lund Sweden

A recursion for sequences of spectra of truncated as well as tailbitten convolutional codes and their duals is derived. The order of this recursion is shown to be less than or equal to the rank of the weight adjacency matrix (WAM) for the minimal encoder of the convolutional code. It is sufficient to know finitely many spectra of these terminated convolutional codes in order to obtain an infinitely long sequence of spectra of their duals.

关键词： Spectra Sufficient convolutional coding Dual Recursion Less than or equal to personal identity

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DIVERSITY COMBINING IN FH BFSK SYSTEMS TO COMBAT PARTIAL BAND JAMMING

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IEEE TRANSACTIONS ON COMMUNICATIONS 1988年第9期36卷 1062-1069页

作者： VISWANATHAN, R TAGHIZADEH, K Department of Electrical Engineering Southern Illinois University at Carbondale Carbondale IL USA

A combiner for a frequency-hopped binary frequency-shift keyed (FH/BFSK) system, called the product-combining receiver (PCR), is introduced. The performance of the PCR is evaluated for the cases of an on/off partial-band noise with optimum-jamming fraction, and worst-case, partial-band tone jamming. The performance of PCR is shown to be comparable to that of the clipper receiver. The effect of diversity combining, along with convolutional coding and ratio-threshold technique, is analyzed. Whereas the clipper requires the knowledge of signal-to-noise ratio for threshold adjustments, the PCR does not require this knowledge for this operation.

关键词： Fighter threshold adjustment knowledge FREQUENCY SHIFT scissor Frequency hopping Receivers convolutional coding diversity reception

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Design and performance analysis of a convolutionally coded overlapping multicarrier DS/CDMA system

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2000年第5期49卷 1950-1967页

作者： Kim, YH Song, I Kim, HG Lee, J Korea Adv Inst Sci & Technol Dept Elect Engn & Comp Sci Div Elect Engn Daejeon South Korea Samsung Elect Co Ltd Core Technol Res Team Yongin South Korea

In this paper, me consider convolutionally coded multicarrier direct-sequence code-division multiple access (DS/CDMA) systems using overlapping subchannels in time-limited and band-limited channels. A tight bound on the bit error probability of the decoder output is obtained in Rayleigh fading channels when the channel state information is ideally available. It is shown that the proposed system, the convolutionally coded overlapping multicarrier DS/CDMA system with a symbol mapping method utilizing the diversity, outperforms the conventional single carrier and nonoverlapping multicarrier systems using the same convolutional code. It is also shown that the proposed system can provide a larger system capacity and more effectively combat the partial band interference than the conventional ones.

关键词： convolutional coding multicarrier direct sequence code division multiple access (DS/CDMA) overlapping subchannels

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USE OF RESIDUAL REDUNDANCY IN THE DESIGN OF JOINT SOURCE CHANNEL CODERS

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IEEE TRANSACTIONS ON COMMUNICATIONS 1991年第6期39卷 838-846页

作者： SAYOOD, K BORKENHAGEN, JC AT&T BELL LABS MURRAY HILL NJ 07974 USA

The need to transmit large amounts of data over a band-limited channel has led to the development of various data compression schemes. Many of these schemes function by attempting to remove redundancy from the data stream. An unwanted side-effect of this approach is to make the information transfer process more vulnerable to channel noise. Efforts at protecting against errors involve the reinsertion of redundancy and an increase in bandwidth requirements. We present a technique for providing error protection without the additional overhead required for channel coding. We start from the premise that, during source coder design, for the sake of simplicity or due to imperfect knowledge, assumptions have to be made about the source which are often incorrect. This results in residual redundancy at the output of the source coder. The residual redundancy can then be used to provide error protection in much the same way as the insertion of redundancy in convolutional coding provides error protection. In this paper we develop an approach for utilizing this redundancy. To show the validity of this approach, we apply it to image coding using DPCM, and obtain substantial performance gains, both in terms of objective as well as subjective measures.

关键词： redundancy differential pulse code modulation image coding Writers convolutional coding ENCODER error protection RESIDUAL PREMISES Channel coding Sake

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On the complexity of bounded distance decoding for the AWGN channel

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IEEE TRANSACTIONS ON INFORMATION THEORY 2002年第5期48卷 1046-1060页

作者： Anderson, JB Lund Univ Dept Informat Technol S-22100 Lund Sweden

Earlier work has derived the storage complexity of the bounded distance decoder (BDD) for binary-channel convolutional codes. We extend this work to the Gaussian noise channel and to partial-response codes. We show that the storage requirement similar to(2(1-R) - 1)(-t) paths for rate-R convolutional codes over the binary channel becomes similar to2(2Rt) over the Gaussian channel, where the decoder must correct t errors. Thus, convolutional coding over the Gaussian channel is not only 3 dB more energy efficient, but its decoding is simpler as well. Next, we estimate the path storage for partial-response codes, i.e., real-number convolutional codes, over the Gaussian channel. The growth rate depends primarily on the bandwidth of the code. A new optimization procedure is devised to measure the maximum storage requirement in Gaussian noise for these two code types. An analysis based on difference equations predicts the asymptotic storage growth for partial response codes.

关键词： convolutional coding decoding decoding complexity intersymbol interference reduction partial response coding

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Construction, analysis and performance of generalised woven codes

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EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS 2004年第2期15卷 79-90页

作者： Bossert, M Dieterich, H Schnug, W Shavgulidze, S Univ Ulm Dept Telecommun & Appl Informat Theory D-89081 Ulm Germany Siemens AG D-89081 Ulm Germany Georgian Tech Univ Dept Digital Commun GE-380075 Tbilisi Georgia

Generalised woven codes (WC) are constructed by combining the woven code structure with the idea of generalised concatenated codes, also known as multi-level codes. The required nested inner convolutional code is analysed. The encoder structure of this new class of codes is described and fundamental code parameters are derived. It is shown that generalised WC have a free distance which is superior to that of comparable WC. Several iterative and non-iterative decoding strategies are discussed. It is shown that the decoding complexity of the nested inner code is not larger than the decoding complexity of its mother code. Finally, bit error rates obtained from simulations are discussed and compared with other code structures like WC. Copyright (C) 2004 AEI.

关键词： Toilets DEcoding Concatenated codes Codes New classes Mother convolutional coding

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Multiservice/multirate pure CDMA for mobile communications

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 1999年第5期48卷 1404-1413页

作者： Azad, H Aghvami, AH Chambers, WC Wireless Facil Inc San Diego CA 92121 USA Univ London Kings Coll Ctr Telecommun Res London WC2R 2LS England

Future mobile communication systems should be able to support a wide range of services with different bit rates. Spread-spectrum code-division;ion multiple-access (CDMA) techniques have attracted much attention to be employed in such a system, Different techniques of CDMA could be used to map low-, medium-, and high-bit rates data into the same allocated bandwidth, including pure or wide-band CDMA, FDM/FH/CDMA, TDM/TH/CDMA, or a hybrid of these techniques. This paper investigates multirate pure CDMA using multiuser interference statistics derived for bath Gaussian and Rayleigh fading channels, Approximation of multiuser/multipath interference, in general, helps in the theoretical approach to error performance evaluation and, in particular, is quite useful for simulation approach in a fading channel, Some results of a multirate pure CDMA system with two services (low- and high-bit rates), for both BPSK and DPSK modulation schemes, are presented and compared.

关键词： BPSK code-division multiple access (CDMA) coherent/noncoherent demodulation convolutional coding differential phase-shift keying (DPSK) direct sequence fading channel multiple-access interference multiservice/multirate

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