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European Wireless Conference (EW)

作者： Ivan Stupia Filippo Giannetti Vincenzo Lottici Luc Vandendorpe Department of Information Engineering University of Pisa Pisa Italy Université Catholique de Louvain Louvain-la-Neuve Belgium

This paper develops cross-layer adaptive modulation and coding as an efficient method for bit interleaved coded OFDM packet transmission. As objective function, we adopt the goodput, or the number of data bits delivered without error per unit of time. After the formalization of the optimization problem through an accurate modeling on the link performance, an iterative solution is derived based on the framework of greedy algorithms. Simulation results show that the proposed method improves upon the performance of static transmission and uniform bit allocation by 2-4 dB.

关键词： Greedy algorithms modulation coding OFDM modulation MIMO Interleaved codes Quality of service Streaming media Bandwidth Fading Automatic control

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Online adaptive modulation and coding with support vector machines

Online adaptive modulation and coding with support vector ma...

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European Wireless Conference (EW)

作者： Robert Daniels Robert W. Heath Wireless Networking and Communication Group Department of Computer and Electrical Engineering University of Texas Austin Austin TX USA

Optimizing the performance of adaptive modulation and coding (AMC) in practice has proven challenging. Prior research has struggled to find link quality metrics that are suitable for look-up-tables and simultaneously provide an injective mapping to error rate in wireless links that feature selective channels with hardware nonlinearities and non-Gaussian noise effects. This paper proposes a novel online support vector machine algorithm, compatible with accurate multidimensional link quality metrics, that is able to optimize AMC to the unique (potentially dynamic) hardware characteristics of each wireless device in selective channels. IEEE 802.11n simulations show that our proposed algorithm allows each individual wireless device to optimize the operating point in the rate/reliability tradeoff through frame-by-frame error evaluation. These simulations also show that our algorithm displays identical performance to alternative online AMC algorithms while drastically reducing complexity.

关键词： modulation coding Support vector machines Error analysis Machine learning algorithms Machine learning Training data Support vector machine classification Wireless communication Hardware Current measurement

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Handover Performance Analysis in Mobile Systems with Adaptive modulation and coding

Handover Performance Analysis in Mobile Systems with Adaptiv...

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International Conference on Digital Telecommunications (ICDT)

作者： Adriana Kalaydzhieva Boris Tsankov Department of Telecommunications Technical University of Sofia Sofia Bulgaria

In this paper, we evaluate the voice traffic performance of an OFDM (Orthogonal Frequency Division Multiplexing) wireless access system. We propose an algorithm for serving handover calls with higher priority than new calls, considering different AMC (adaptive modulation and coding) modes. The purpose is to efficiently utilize the scarce radio resources in order to improve the system performance.

关键词： Performance analysis Adaptive systems modulation coding Quality of service Wireless networks OFDM modulation Bandwidth System performance Degradation Urban areas

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Evaluation of Cramer-Rao Bounds for Phase Estimation of Coded Linearly Modulated Signals

Evaluation of Cramer-Rao Bounds for Phase Estimation of Code...

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IEEE Vehicular Technology Conference

作者： Nan Wu Hua Wang Hongjie Zhao Huafeng Liu Jingming Kuang School of Information and Electronics Beijing Institute of Technology Research Center of Beijing Space Information Relay Transmission Technology

ISBN: (纸本)9781479944811

The evaluation of Cramer-Rao Bounds (CRBs) for phase estimation of coded linearly modulated signals are difficult due to the intractable expectations of the likelihood function with respect to coded symbols. In this paper, we propose two methods towards this end. The first one is a semi-analytical method for coded QPSK signals. Based on Gaussian approximation of extrinsic information, the expression of CRB is derived in terms of signal-to-noise ratio (SNR) and the mean of extrinsic information in closed form. For high-order modulations, e.g., 16QAM signal, we propose a numerical method based on multidimensional Gauss-Hermite Quadrature (GHQ). It is shown that, without suffering from the linearization error, the results of numerical method by GHQ outperform the semi-analytical results, and the former are consistent with that of the Monte Carlo simulations for systems with different codes and numbers of decoding iterations.

关键词： Monte Carlo methods approximation theory decoding iterative methods modulation coding phase estimation quadrature amplitude modulation quadrature phase shift keying 16QAM signal Cramer-Rao bounds Gaussian approximation Monte Carlo simulations SNR coded QPSK signals coded linearly modulated signals coded symbols decoding iterations high-order modulations intractable expectations likelihood function linearization error multidimensional Gauss-Hermite quadrature semianalytical method signal-to-noise ratio Iterative decoding Phase estimation Phase shift keying Phase estimation Monte Carlo technique Cramer-Rao bounds signal to noise ratios Quadrature phase shift keying Likelihood Functions Gaussian approximation modulation coding Phase shift keying Iterative decoding iterative methods Quadrature amplitude modulation Approximation Theory High order modulation DEcoding

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Link Adaptation Scheme for Uplink MIMO Transmission with Turbo Receivers

Link Adaptation Scheme for Uplink MIMO Transmission with Tur...

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IEEE Vehicular Technology Conference

作者： Yun Xue Qiang Sun Bin Jiang Xiqi Gao National Mobile Communications Research Laboratory Southeast University

ISBN: (纸本)9781479944811

In this paper, the turbo minimum mean square error-parallel interference cancelation (Turbo MMSE-PIC) receiver is incorporated with link adaptation schemes to achieve promising performance gains for uplink MIMO transmission, in parallel, adapt the link in the actual channel conditions with assist from performance prediction technology. We first predict the turbo receiver's performance as a basic metric for link adaptation scheme. Then, a new strategy of selecting the precoding matrices, the number of spatially multiplexed layers as well as modulation coding schemes is proposed, resulting in the proposed three-steps selection. In this method, the number of layers and modulation coding schemes to be feedback is initialized and used to set a shortened range of them. Then the number of layers is updated to take full advantage of iterative processing, instead of the initial value in the conventional strategy. In so doing, the benefit of turbo receivers is efficiently claimed while low computational complexity can be achieved.

关键词： MIMO communication computational complexity interference suppression iterative methods least mean squares methods modulation coding radio receivers Turbo MMSE-PIC receiver iterative processing link adaptation scheme parallel interference cancelation turbo minimum mean square error turbo receivers uplink MIMO transmission Joints MIMO Mutual information Prediction methods Receivers Throughput Uplink modulation coding complexity classes up link Least squares method Receivers MIMO communication Prediction methods multiple input multiple output systems radio receivers suppression of interference iterative methods Throughput Turbo Worm gears Joints

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Superposition modulation with Irregular Convolutional coding

Superposition Modulation with Irregular Convolutional Coding

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IEEE Global Communications Conference (GLOBECOM)

作者： Noemm, Meelis Mourad, Alaa Hoeher, Peter Adam Univ Kiel Fac Engn D-24143 Kiel Germany

ISBN: (纸本)9781467309219;9781467309202

Bijective mapping techniques with uniformly distributed constellation diagrams, like PSK and QAM, are standard in today's communications systems. Yet, it is well known that without additional effort in form of active signal shaping, bijective mapping techniques are not capacity achieving. In recent years, an alternative technique called superposition modulation (SM) has been investigated, which theoretically is capacity achieving on the Gaussian channel. However, non-bijective mapping (which can be interpreted as lossy source coding) is challenging with respect to the design of proper channel codes. In this paper, the suitability of irregular convolutional coding in conjunction with superposition modulation is investigated. With proper code design, this combination is capable of achieving 6 bits/symbol at just 0.7 dB away from the Shannon capacity limit given a memory-4 mother code.

关键词： Gaussian channels channel coding convolutional codes modulation coding

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Multi-Edge-Type Low-Density Parity-Check Codes for Bandwidth-Efficient modulation

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IEEE TRANSACTIONS ON COMMUNICATIONS 2013年第1期61卷 43-52页

作者： Zhang, Lei M. Kschischang, Frank R. Univ Toronto Dept Elect & Comp Engn Toronto ON M5S 3G4 Canada

A method of designing low-density parity-check codes for bandwidth-efficient high-order modulation is proposed. A multi-edge-type LDPC code ensemble is used to improve the correspondence between modulation bit-channel capacity and bit-level protection in a bit-interleaved coded modulation system. A key innovation is the development of a multi-dimensional extrinsic information transfer (EXIT) vector field technique for the analysis and design of multi-edge-type codes. A condition, sufficient for the decoder to converge, is derived on the multi-dimensional EXIT vector field, and this condition is used as a constraint in code optimization. Code designs indicate that the proposed method produces codes matching the performance of codes designed using best available methods in ensemble threshold, and is capable of achieving identical finite-length error rates with shorter block-lengths. In addition to simplified design complexity, the resulting codes allow for low-complexity implementation and rate-adaptivity, and hence are well-suited for adaptive modulation systems.

关键词： binary codes error-correction codes iterative decoding modulation coding optimization

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Cross-layer channel selection and reward-based power allocation for increasing system capacity and reward in multiple-input-multiple-output wireless communications

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IET COMMUNICATIONS 2013年第10期7卷 1032-1041页

作者： Chang, Ben-Jye Liang, Ying-Hsin Tsai, Tzung-Shiun Natl Yunlin Univ Sci & Technol Dept Comp Sci & Informat Engn Taipei Taiwan Nan Kai Univ Technol Dept Multimedia Animat & Applicat Caotun Township Nantou Taiwan Chaoyang Univ Technol Dept Comp Sci & Informat Engn Taichung Taiwan

For increasing network bandwidth and guaranteeing quality of service in WiMAX, IEEE 802.16 m proposes the multiple-input-multiple-output (MIMO) technique that offers compatible specifications with the existing IEEE 802.16 family specifications. However, the performance of the IEEE 802.16 MIMO specification is significantly degraded in the high-mobility environment and high communication interference. As a result, a sender easily uses inaccurate modulation and coding scheme (MCS) and improper power allocation for different-priority users having different received signal-to-noise ratios. The system capacity is thus affected significantly. Additionally, the multiuser MIMO systems seldom consider that different-priority users and different-class traffic bring different rewards to the system. This study thus proposes a cross-layer reward-based approach (namely CLR) that consists of three schemes: adaptive modulation and coding determination, cross-layer dynamic channel selection, and reward-based weighting power allocation. The proposed CLR approach achieves accurate channel state information determination, optimal channel selection, and adaptive reward power allocation. Numerical results demonstrate that the proposed approach significantly outperforms the other approaches in system reward, system capacity, and the accuracy of the MCS determination.

关键词： adaptive modulation channel capacity MIMO communication modulation coding quality of service radiofrequency interference telecommunication traffic WiMax wireless channels cross-layer channel selection reward-based power allocation system capacity multiple-input-multiple-output wireless communications network bandwidth quality of service WiMAX IEEE 802.16 MIMO specification high-mobility environment high communication interference modulation and coding scheme MCS different-priority users received signal-to-noise ratios different-class traffic cross-layer reward-based approach adaptive modulation coding determination cross-layer dynamic channel selection reward-based weighting power allocation CLR approach channel state information determination optimal channel selection adaptive reward power allocation system capacity MCS determination

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Design and Implementation of an "Approximate" Communication System for Wireless Media Applications

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IEEE-ACM TRANSACTIONS ON NETWORKING 2013年第4期21卷 1035-1048页

作者： Sen, Sayandeep Zhang, Tan Gilani, Syed Srinath, Shreesha Banerjee, Suman Addepalli, Sateesh Univ Wisconsin Madison WI 53706 USA Cisco Syst San Jose CA 95134 USA

All practical wireless communication systems are prone to errors. At the symbol level, such wireless errors have a well-defined structure: When a receiver decodes a symbol erroneously, it is more likely that the decoded symbol is a good "approximation" of the transmitted symbol than a randomly chosen symbol among all possible transmitted symbols. Based on this property, we define approximate communication, a method that exploits this error structure to natively provide unequal error protection to data bits. Unlike traditional [forward error correction (FEC)-based] mechanisms of unequal error protection that consume additional network and spectrum resources to encode redundant data, the approximate communication technique achieves this property at the PHY layer without consuming any additional network or spectrum resources (apart from a minimal signaling overhead). Approximate communication is particularly useful to media delivery applications that can benefit significantly from unequal error protection of data bits. We show the usefulness of this method to such applications by designing and implementing an end-to-end media delivery system, called Apex. Our Software Defined Radio (SDR)-based experiments reveal that Apex can improve video quality by 5-20 dB [peak signal-to-noise ratio (PSNR)] across a diverse set of wireless conditions when compared to traditional approaches. We believe that mechanisms such as Apex can be a cornerstone in designing future wireless media delivery systems under any error-prone channel condition.

关键词： Algorithms design measurement modulation coding performance evaluation

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Maximum Euclidean distance network coded modulation for asymmetric decode-and-forward two-way relaying

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IET COMMUNICATIONS 2013年第10期7卷 988-998页

作者： Chen, Wei Cao, Zhigang Hanzo, Lajos Tsinghua Univ Dept Elect Engn Beijing 100084 Peoples R China Univ Southampton Sch Elect & Comp Sci Southampton Hants England

Network coding (NC) compresses two traffic flows with the aid of low-complexity algebraic operations, hence holds the potential of significantly improving both the efficiency of wireless two-way relaying, where each receiver is collocated with a transmitter and hence has prior knowledge of the message intended for the distant receiver. In this contribution, network coded modulation (NCM) is proposed for jointly performing NC and modulation. As in classic coded modulation, the Euclidean distance between the symbols is maximised, hence the symbol error probability is minimised. Specifically, the authors first propose set-partitioning-based NCM as an universal concept which can be combined with arbitrary constellations. Then the authors conceive practical phase-shift keying/quadrature amplitude modulation (PSK/QAM) NCM schemes, referred to as network coded PSK/QAM, based on modulo addition of the normalised phase/amplitude. To achieve a spatial diversity gain at a low complexity, a NC oriented maximum ratio combining scheme is proposed for combining the network coded signal and the original signal of the source. An adaptive NCM is also proposed to maximise the throughput while guaranteeing a target bit error probability (BEP). Both theoretical performance analysis and simulations demonstrate that the proposed NCM can achieve at least 3 dB signal-to-noise ratio gain and two times diversity gain.

关键词： adaptive codes communication complexity diversity reception error statistics minimisation modulation coding phase shift keying quadrature amplitude modulation radio receivers radio transmitters telecommunication traffic network coding decode and forward communication relay networks (telecommunication) maximum Euclidean distance network coded modulation asymmetric decode-and-forward two-way relaying traffic flow compression low-complexity algebraic operations wireless two-way relaying efficiency improvement wireless receiver wireless transmitter symbol error probability minimisation set-partitioning-based NCM phase shift keying quadrature amplitude modulation PSK-QAM NCM schemes network coded PSK-QAM modulo addition normalised phase normalised amplitude spatial diversity gain NC oriented maximum ratio combining scheme network coded signal adaptive NCM throughput maximisation BEP performance analysis signal-to-noise ratio gain

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