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MILCOM, Military Communications Conference

作者： J. Michael Frye Michael R. Masse Michael B. Pursley Clemson University Clemson SC USA

ISBN: (纸本)9781424452385

Effective adaptation of error-control coding in a packet radio network requires certain statistics to be developed in the demodulator and decoder of the receiving radio during the reception of each packet. The statistics from one packet are employed to select the code for the next packet. The design and evaluation of cross-layer protocols that use such statistics typically require numerous simulations of the network, and each simulation of the network has numerous embedded simulations of the demodulators and decoders that are in the radios. The embedded simulations of the decoder are especially computationally intensive if the radios employ iterative decoding. We present a method for the direct generation of receiver statistics that avoids the time-consuming embedded simulations of the demodulator and decoder, thereby accelerating the process of designing, developing, and evaluating adaptive cross-layer protocols. The required statistics are modeled as random variables that can be generated quickly, yet their distributions approximate the distributions of the actual receiver statistics. The method is illustrated for an adaptive coding protocol in a network of frequency-hop (FH) radios that employ turbo product codes with soft-decision iterative decoding. Results are given on the quality of the approximations and the reductions in simulation time that they provide. Our method for the direct generation of receiver statistics provides even greater benefits in the design and evaluation of higher-layer protocols that employ receiver statistics.

关键词： Acceleration adaptive coding Protocols Frequency Computational modeling Iterative decoding Statistics Demodulation Statistical distributions Packet radio networks

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Rate enhancement of BICM-OFDM with adaptive coding and modulation via a bisection approach

Rate enhancement of BICM-OFDM with adaptive coding and modul...

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IEEE Workshop on Signal Processing Advances in Wireless Communications (SPAWC)

作者： Carsten Bockelmann Dirk Wubben Karl-Dirk Kammeyer Department of Communications Engineering University of Brethemen Germany

adaptive communication is an important topic to enhance the capabilities of future communication systems. Especially in combination with Orthogonal Frequency Division Multiplexing (ODFM) bit and power loading schemes have been devised to enhance the transmit rate of communication systems. The consideration of channel coding in the optimization is an obvious requirement. In the past, though, mainly uncoded systems have been investigated allowing for further enhancements. In this paper we propose a new scheme to adapt code rate and modulation by solving the convex optimization problem based on a bisection approach in order to maximize the achievable data rate at a fixed target error rate.

关键词： adaptive coding Modulation coding Channel coding Communication systems Error analysis Bit error rate OFDM modulation AWGN Frequency domain analysis Power engineering and energy

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On the adaptive Software-Defined LDPC-Coded Multidimensional Spatial-MIMO Multiband Generalized OFDM Enabling Beyond 10-Tb/s Optical Transport

IEEE PHOTONICS JOURNAL

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IEEE PHOTONICS JOURNAL 2013年第1期5卷

作者： Djordjevic, Ivan B. Liu, Tao Wang, Ting Univ Arizona Dept Elect & Comp Engn Tucson AZ 85721 USA NEC Labs Amer Princeton NJ 08540 USA

Future Internet technologies will be affected by limited bandwidth of information infrastructure, high energy consumption, and heterogeneity of optical networks. In order to simultaneously solve these problems, we propose an adaptive multidimensional mode-multiplexed software-defined LDPC-coded modulation scheme suitable for few-mode-fiber-optic communications enabling beyond 10-Tb/s optical transport. This scheme employs the optimum multidimensional signal constellations and generalized OFDM operation principle. The proposed scheme significantly outperforms the corresponding scheme based on conventional polarization-division multiplexed QAM.

关键词： Microwave photonics signal processing few-mode/few-core fiber-optics communications mode division multiplexing (MDM) low-density parity-check (LDPC) codes OFDM adaptive coding spatial MIMO multidimensional coded modulation

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Context quantization based on the modified genetic algorithm with K-means

Context quantization based on the modified genetic algorithm...

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International Conference on Natural Computation (ICNC)

作者： Min Chen Jianhua Chen Department of electronic engineering Yunnan University Kunming China Dianchi College Yunnan University Kunming China

In this paper, the context quantization for I-ary sources based on a modified genetic algorithm is presented. In this algorithm, the optimal context quantizer is described by the chromosome which contains the optimal number of classes and the corresponding cluster centers. The adaptive code length is used to evaluate the fitness value to find the best chromosome. The rules for the selection, the crossover and the mutation operations are discussed. A K-means operator is incorporated in each iteration to accelerate the convergence of the algorithm. The optimized context quantizer can be obtained without the prior knowledge of the number of classes. Simulations indicate that the proposed algorithm produces results that approximate the best result obtained by the K-means-based context quantization with lower computational complexity.

关键词： Context Biological cells Quantization (signal) adaptive coding Context modeling Probability distribution Clustering algorithms

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A comparative analysis of results data clustering with variants of differential evolution optimization

A comparative analysis of results data clustering with varia...

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International Conference on Information Management in the Knowledge Economy (IMKE)

作者： Anima Naik Suresh Ch. Satapathy K. Parvathi MITS Rayagada India ANITS Vishakapatnam India CUTM Paralakhemundi

Differential evolution (DE) has emerged as one of the fast, robust, and efficient global search heuristics algorithm of current interest. This paper describes an application of DE to the clustering of unlabeled data sets. Here it has been used different variants of DE for clustering the data set. It is shown how different variants of DE can be used to find the centroids of a user specified number of clusters. These algorithms are evaluated on some real life datasets and compared their performances. The convergence characteristics of each variant are shown for different datasets. This study may be very useful for researchers for comparison purposes.

关键词： Vectors Clustering algorithms adaptive coding Sociology Statistics Quantization (signal) Iris

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An Algorithm of adaptive Video coding Scheme Based on FGS

An Algorithm of Adaptive Video Coding Scheme Based on FGS

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WRI International Conference on Communications and Mobile Computing

作者： Yang Jie Wang Kecheng Chen De Wuhan Univ Technol Wuhan 430063 Peoples R China Zhe Jiang Univ Zhe Jiang 310058 Peoples R China

ISBN: (纸本)9780769535012

An improved fine granular adaptive video coding algorithm based on fine granular scalable (FGS) is presented in this paper, which chooses high quality reference in enhancement layer coding, and uses the leaky prediction techniques which can control error propagation by the leaky factor. The simulation and experiments indicate that the proposed scheme can make a better trade-off between the coding efficiency and drift attenuation.

关键词： video adaptive coding fine granular scalable (FGS)

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adaptive coding and prediction of sources with large and infinite alphabets

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IEEE TRANSACTIONS ON INFORMATION THEORY 2008年第8期54卷 3808-3813页

作者： Ryabko, Boris Y. Astola, Jaakko Gammerman, Alex Russian Acad Sci Siberian Branch Inst Computat Technol Novosibirsk 630102 Russia Tampere Univ Technol FIN-33101 Tampere Finland Univ London Dept Comp Sci London England

The problem of predicting a sequence x(1), x(2), .... generated by a discrete source with unknown statistics is considered. Each letter x(t+1) is predicted using the information on the word x(1), x(2), .... x(t) only. This problem is of great importance for data compression, because of its use to estimate probability distributions for PPM algorithms and other adaptive codes. On the other hand, such prediction is a classical problem which has received much attention. Its history can be traced back to Laplace. We address the problem where the sequence is generated by an independent and identically distributed (i.i.d.) source with some large (or even infinite) alphabet and suggest a class of new methods of prediction.

关键词： adaptive coding Laplace problem of succession lossless data compression prediction of random processes Shannon entropy source coding

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adaptive Scheduling for Multicasting Hard Deadline Constrained Prioritized Data via Network coding

Adaptive Scheduling for Multicasting Hard Deadline Constrain...

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IEEE Global Communications Conference

作者： Tuan T. Tran Hongxiang Li Weiyao Lin Lingjia Liu Samee U. Khan Department of Electrical and Computer Engineering J.B. Speed School of Engineering University of Louisville Institute of Image Communication and Information Processing Shanghai Jiaotong University Department of Electrical Engineering and Computer Science The University of Kansas Department of Electrical and Computer Engineering North Dakota State University

ISBN: (纸本)9781467309202

Network coding offers a promising platform for multicast transmission by approaching its min-cut capacity. However, pushing the network throughput toward this upper bound comes with a sacrifice in delivery delay due to the decoding procedure that requires performing batch of coded packets. Further, in some transmission scenarios where the receivers experience deep fading or unable to collect a full set of the transmitted data, no useful information is recovered. The effect is more severe in the networks where the transmitted information has priority structure with hard deadline constraint due to the limited delivery time and data interdependencies. In this paper, we consider single-hop wireless networks where the transmitter wishes to multicast hard deadline constrained prioritized data to many receivers over lossy channels. We first study the network performance of a variety of transmission techniques, depending on how the transmitter schedules transmission in each time slot. We then propose an adaptive encoding and scheduling technique to maximize the network throughput. To find the optimal transmission scheduling at the presence of the network dynamics, we cast the problem in the framework of Markov Decision Processes (MDP) and use backward induction method to find an optimal solution. We further propose simulation-based algorithm and greedy scheduling technique that obtain high performance with much lower time complexity. Both analytical and simulation results have been provided to corroborate the effectiveness of the proposed techniques.

关键词： Multicast Hard deadline constraint Prioritized transmission adaptive scheduling Network coding adaptive scheduling Network coding Multicast Network throughput adaptive coding deep fading Transmission techniques

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On the design of coded MIMO systems

On the design of coded MIMO systems

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International Conference on Communications and Information Technology

作者： Mohamad Sayed Hassan Ammar El Falou Charlotte Langlais Alten Sir Universite de Rennes 1 Institut Mines-Telecom

ISBN: (纸本)9781467353069

In this paper, we investigate two approaches which deal with the construction of space-time block (STB) codes for a system possessing a forward error correcting (FEC) code at the transmitter side. The first approach designs the STB codes to be optimal for a system equipped by a turbo MMSE equalizer at the receiver side, with a minimum peak to average power ratio (PAPR) constraint. The second one proposes to design the STB codes according to a non-asymptotic design criterion based on the bitwise mutual information (BMT) maximization at a specific target SNR. Performance assessments of designed codes are validated by Monte Carlo simulations.

关键词： MIMO Receivers Peak to average power ratio Signal to noise ratio Detectors Complexity theory adaptive coding

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adaptive Modulation and coding for Generalized Fading Channels

Adaptive Modulation and Coding for Generalized Fading Channe...

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9th International Conference on Telecommunications in Modern Satellite, Cable and Broadcasting Services

作者： Djordjevic, Ivan B. Djordjevic, Goran T. Univ Arizona Dept Elect & Comp Engn 1230 E Speedway Blvd Tucson AZ 85721 USA Univ Nis Telecommun Dept Fac Elect Engn Montenegro 18000 Serbia

ISBN: (纸本)9781424443819

The adaptive modulation and coding can provide robust and spectrally efficient transmission over generalized alpha-mu (or generalized Gamma) wireless fading channels. The key idea of our proposal is to transmit the low-density parity-check (LDPC) encoded sequence over the generalized fading channel, feedback the channel state information of by an RF feedback channel, and adapt the powers and rates of so that the channel capacity is maximized. The optimal power adaptation policy maximizing the channel capacity is derived. We show that deep fades can be tolerated with proposed scheme.

关键词： adaptive modulation adaptive coding Generalized alpha-mu wireless fading channels Low-density parity-check (LDPC) codes

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