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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2010年第8期59卷 3766-3778页

作者： Jensen, Tobias Lindstrom Kant, Shashi Wehinger, Joachim Fleury, Bernard Henri Aalborg Univ Dept Elect Syst DK-9220 Aalborg Denmark LTE & 3G Modem Solut ST Ericsson AT AB S-22183 Lund Sweden Infineon Technol AG Wireless Solut D-85579 Neubiberg Germany

We investigate link-quality metrics (LQMs) based on raw bit-error-rate, effective signal-to-interference-plus-noise ratio, and mutual information (MI) for the purpose of fast link adaptation (LA) in communication systems employing orthogonal frequency-division multiplexing and multiple-input-multiple-output (MIMO) antenna technology. From these LQMs, the packet error rate (PER) can be estimated and exploited to select the modulation and coding scheme (MCS) among a class of candidate MCSs that achieves the maximum throughput for the current channel state under a specified target PER objective. We propose a novel MI-based LQM and compare the PER-estimation accuracy obtained with this LQM with that resulting from using other LQMs by means of comprehensive Monte Carlo simulations. Search methods for the MCS in the class that is most suitable for a given channel state are presented. An algorithm for obtaining a practical upper bound on the throughput of any LA scheme is proposed. The investigated LQMs are applied to the IEEE 802.11n standard with a 2 x 2 MIMO configuration and practical channel estimation. The proposed MI-based LQM yields the highest PER estimation accuracy, and its throughput shows only 1.7 dB signal-to-noise-ratio (SNR) loss with respect to the upper bound but up to 9.5 dB SNR gain, compared to the MCS maximizing the throughput for the current noise variance.

关键词： adaptive modulation and coding channel-state information fading feedback delay link adaptation (LA) link-quality metrics (LQMs) multiple-input-multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) packet-error-rate (PER) estimation

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adaptive Turbo Coded modulation for Shallow Underwater Acoustic Communications

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WIRELESS PERSONAL COMMUNICATIONS 2014年第2期78卷 1231-1248页

作者： Clemente, M. Carmen Ruiz-Vega, Fernando Otero, Pablo Paris, Jose F. Univ Malaga Dept Ingn Comunicac E-29071 Malaga Spain

In this paper the performance of a wireless communications system over shallow underwater acoustic channels is investigated when adaptive modulation and coding techniques with receiver diversity are used. It is assumed that the communication system experiences Ricean shadowed fading. We obtain the analytical figures of the proposed rate-adaptive transmission schemes, emphasizing in the spectral efficiency and the average bit error rate. These analytical expressions are compared to Monte-Carlo simulations corroborating the analytical results.

关键词： Underwater acoustic communications Spectral efficiency Average bit error rate adaptive modulation and coding

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An end-to-end embedded approach for multicast/broadcast of scalable video over multiuser CDMA wireless networks

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IEEE TRANSACTIONS ON MULTIMEDIA 2007年第3期9卷 655-667页

作者： Chan, Yee Sin Modestino, James W. Qu, Qi Fan, Xingzhe Univ Miami Dept Elect & Comp Engn Coral Gables FL 33124 USA Univ Calif San Diego Dept Elect & Comp Engn La Jolla CA 92093 USA

We investigate an embedded multicast/broadcast approach for transport of digital video over spread-spectrum code-division multiple access (CDMA) cellular networks. Previous work has shown that the incorporation of a scalable source coding scheme with multiresolution modulation provides a promising design paradigm for the practical realization of the information-theoretic performance predictions originally developed by Cover [1], which demonstrated that optimal multicast/broadcast performance could be achieved by an embedded transmission scheme. Hence, the major technical challenge associated with the design of an end-to-end embedded multicast/broadcast system is how to match an embedded modulation constellation with a scalable source coding scheme. In this work, taking into consideration both the interference-limited and bandwidth-limited characteristics of a CDMA system, we provide a cross-layer approach incorporating adaptive power allocation and channel coding strategies and effectively match a discrete cosine transform based scalable motion-compensated video encoder to an embedded multiresolution modulation scheme to simultaneously deliver a basic quality-of-service (QoS) to less capable receivers while maximizing both the QoS for more capable receivers and the system capacity. We demonstrate the efficacy of this approach using the ITU-T H.263+ video scalable hybrid coder, although the approach is generally extensible to other scalable coding schemes as well.

关键词： adaptive modulation and coding code-division multiple access (CDMA) cross-layer drift control embedded transmission H.263+ joint source-channel coding joint source coding-power control multicast/broadcast turbo codes wireless video

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A cross layer framework of Radio Resource Allocation for QoS provisioning in multi-channel fading wireless networks

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WIRELESS NETWORKS 2020年第1期26卷 403-419页

作者： Palit, Basabdatta Das, Suvra Sekhar Indian Inst Technol GS Sanyal Sch Telecommun Kharagpur W Bengal India

In this paper, we present an analytical framework for the performance evaluation of Radio Resource Allocation (RRA) in Orthogonal Frequency Division Multiple Access (OFDMA) networks. We focus on Quality of Service (QoS) guaranteed traffic whose capacity, in terms of the number of active user connections, depends on the users' QoS requirements and channel conditions, and the RRA algorithm. The required QoS is guaranteed by restricting the number of admitted calls, which in turn requires an accurate estimate of the QoS metrics and capacity supported by the RRA when a new call arrives. These estimates for OFDMA networks are variable and usually obtained through time-consuming offline computer simulations. Mathematical frameworks on the other hand yield timely and accurate results. However, earlier known works on analytical modelling of RRA either consider a single channel with random traffic arrivals or multiple channels with full buffer data traffic. In contrast, we develop a queueing theoretic framework considering randomly arriving QoS-guaranteed traffic in a variable-rate multi-channel multi-class OFDMA network. The framework can be used online leading to better dynamic Call Admission Control. We characterize the RRA algorithm using a scheduler control parameter which can regulate the call blocking probability while providing predefined QoS constraints. We model the RRA as a variable service rate, multi-server, multi-class, finite buffer queueing system and verify the derived QoS metrics using extensive Monte-Carlo discrete event simulations.

关键词： Packet Scheduling Radio Resource Allocation OFDMA adaptive modulation and coding Queueing Priority Markov Chain Multi-class Call Admission Control Cross-layer

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New transmission scheme to enhance throughput of DF relay network using rate and power adaptation

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INTERNATIONAL JOURNAL OF ELECTRONICS 2017年第9期104卷 1500-1513页

作者： Taki, Mehrdad Heshmati, Milad Univ Qom Dept Elect Engn Qom Iran

This paper presents a new transmission scheme for a decode and forward (DF) relay network using continuous power adaptation while independent average power constraints are provisioned for each node. To have analytical insight, the achievable throughputs are analysed using continuous adaptation of the rates and the powers. As shown by numerical evaluations, a considerable outperformance is seen by continuous power adaptation compared to the case where constant powers are utilised. Also for practical systems, a new throughput maximised transmission scheme is developed using discrete rate adaptation (adaptive modulation and coding) and continuous transmission power adaptation. First a 2-hop relay network is considered and then the scheme is extended for an N-hop network. Numerical evaluations show the efficiency of the designed schemes.

关键词： Link adaptation DF relay adaptive modulation and coding

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Fuzzy-Based Optimized QoS-Constrained Resource Allocation in a Heterogeneous Wireless Network

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INTERNATIONAL JOURNAL OF FUZZY SYSTEMS 2016年第6期18卷 1131-1140页

作者： Taki, Mehrdad Heshmati, Milad Omid, Yasaman Univ Qom Qom Iran

A new joint scheduling and link adaptation scheme is designed using fuzzy logic. A unified scheduler is designed which provides different throughput requirements and optimally allocates the shared media to the users based on their importance. adaptive modulation, coding, and transmit power is used provisioning an average power constraint depending on each user's power supply. Various bit error rate and QoS-delay constraints are provided for all links. Numerical evaluations show that the proposed fuzzy-based scheme has the performance quite close to the analytical approach, however, with substantially lower complexity.

关键词： Resource allocation Scheduling adaptive modulation and coding Fuzzy logic

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Joint AMC and Packet Fragmentation for Error Control Over Fading Channels

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2010年第6期59卷 3070-3080页

作者： Zhang, Ruonan Cai, Lin Univ Victoria Dept Elect & Comp Engn Victoria BC V8W 3P6 Canada

Error control is critical for wireless networks to combat channel fading and ensure efficient resource utilization. adaptive modulation and coding (AMC) in the physical (PHY) layer and packet fragmentation and automatic repeat request (ARQ) in the link layer are widely used error-control mechanisms. However, how to jointly optimize them in both layers for high-rate wireless networks is still open. In this paper, using the WiMedia ultrawideband (UWB) networks as an example, we first develop a general analytical framework to quantify the link delay and loss performance considering the channel fading, the joint error-control mechanisms, and the arbitrary reservation-based media access control (MAC) protocol. Second, we introduce a cross-layer design to optimize the PHY-layer AMC and the link-layer packet fragmentation and propose a joint-adaptation mechanism that is simple to implement and has near-optimal performance. Numerical results reveal that fragmentation has a greater impact than AMC on the delay and loss performance for marginal links and that the proposed joint-adaptation strategy is efficient for high-rate wireless networks.

关键词： adaptive modulation and coding automatic repeat request error control fading channels packet fragmentation queueing analysis reservation-based medium access control

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A unified approach to QoS-guaranteed scheduling for channel-adaptive wireless networks

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PROCEEDINGS OF THE IEEE 2007年第12期95卷 2410-2431页

作者： Wang, Xin Giannakis, Georgios B. Marques, Antonio G. Florida Atlantic Univ Dept Elect Engn Boca Raton FL 33431 USA Univ Minnesota Dept Elect & Comp Engn Minneapolis MN 55455 USA Rey Juan Carlos Univ Dept Signal Theory & Commun Madrid 28943 Spain

Scheduling amounts to allocating optimally channel, rate and power resources to multiple connections with diverse quality-of-service (QoS) requirements. It constitutes a throughput-critical task at the medium access control layer of today's wireless networks that has been tackled by seemingly unrelated information-theoretic and protocol design approaches. Capitalizing on convex optimization and stochastic approximation tools, the present paper develops a unified framework for channel-aware QoS-guaranteed scheduling protocols for use in adaptive wireless networks whereby multiple terminals are linked through orthogonal fading channels to an access point, and transmissions are (opportunistically) adjusted to the intended channel. The unification encompasses downlink and uplink with time-division or frequency-division duplex operation;full and quantized channel state information comprising a few bits communicated over a limited-rate feedback channel;different types of traffic (best effort, non-real-time, real-time);uniform and optimal power loading;off-line optimal scheduling schemes benchmarking fundamentally achievable rate limits;as well as on-line scheduling algorithms capable of dynamically learning the intended channel statistics and converging to the optimal benchmarks from any initial value. The take-home message offers an important cross-layer design guideline: judiciously developed, yet surprisingly simple, channel-adaptive, on-line schedulers can approach information-theoretic rate limits with QoS guarantees.

关键词： adaptive modulation and coding convex optimization quality of service (QoS) scheduling and resource allocation stochastic approximation

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adaptive Uniform Entropy Loading for SSB-DMT Systems

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JOURNAL OF LIGHTWAVE TECHNOLOGY 2019年第23期37卷 5961-5970页

作者： Chen, Xi Chen, Yizhao Tang, Ming Tong, Tianhao Fu, Songnian Liu, Deming Huazhong Univ Sci & Technol Sch Opt & Elect Informat Wuhan Natl Lab Optoelect Wuhan 430074 Peoples R China Huazhong Univ Sci & Technol Sch Opt & Elect Informat Next Generat Internet Access Natl Engn Lab Wuhan 430074 Peoples R China

In this paper, we proposed a simple uniform entropy loading (UEL) algorithm to adaptively load the same entropy for all the subcarriers according to the channel state information. Thanks to the signal-to-noise ratio (SNR) equalization effect of precoding, only one distribution matcher is used for UEL, maximally reducing the complexity of entropy loading. The proposed algorithm is based on the relationship between the optimal information bits per symbol (IBPS) and SNR for probabilistically shaped quadrature amplitude modulation (PS QAM) under the constraint of normalized generalized mutual information (NGMI) considering the implementation of constant composition distribution matching (CCDM) and off-the-shelf forward error correction (FEC) code. Different from generalized mutual information (GMI), IBPS intuitively represents practical performance. Besides, the relationship between IBPS and SNR for conventional QAM and time domain hybrid QAM (TDHQ) are also calculated to perform the well-known bit power loading (BPL) algorithm, Levin-Campello (LC) algorithm, and TDHQ assisted adaptive loading (AL) algorithm, respectively. Based on theoretical analysis, to our best knowledge, we first found that precoding procedure adopted by TDHQ assisted AL and UEL scheme degrades Shannon capacity compared to water-filling algorithm, the upper limit of BPL algorithms. However, benefiting from shaping gain of PS QAM, the proposed UEL algorithm achieves higher net data rate (NDR) and lower peak-to-average power ratio (PAPR) than the LC algorithm, which is demonstrated by the simulations and experiments in single sideband discrete multi-tone (SSB-DMT) systems. According to the experimental results, up to 3.2% NDR improvement and 0.82 dB PAPR reduction are realized by the UEL algorithm compared to the LC algorithm. The UEL algorithm also outperforms TDHQ assisted AL algorithm by the average NDR gain of up to 8.0%. The simple and effective advantages make the proposed UEL scheme suitable f

关键词： adaptive modulation and coding bit and power loading discrete multi-tone precoding probabilistic shaping single sideband modulation

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Performance of adaptive Trellis Coded modulation Applied to MC-CDMA with Bi-orthogonal Keying

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IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 2009年第11期E92A卷 2837-2843页

作者： Tanaka, Hirokazu Yamasaki, Shoichiro Haseyama, Miki Toshiba Co Ltd Kawasaki Kanagawa 2120013 Japan Polytech Univ Sagamihara Kanagawa 2291196 Japan Hokkaido Univ Sapporo Hokkaido 0600814 Japan

A Generalized Symbol-rate-increased (GSRI) Pragmatic adaptive Trellis Coded modulation (ATCM) is applied to a Multi-carrier CDMA (MC-CDMA) system with bi-orthogonal keying is analyzed. The MC-CDMA considered in this paper is that the input sequence. of a bi-orthogonal modulator has code selection bit sequence and sign bit sequence. In [9], an efficient error correction code using Reed-Solomon (RS) code for the code selection bit sequence has been proposed. However, since BPSK is employed for the sign bit modulation, no error correction code is applied to it. In-order to realize a high speed wireless system, a multi-level modulation scheme (e.g. MPSK, MQAM, etc.) is desired. In this paper, we investigate the performance of the MC-CDMA with bi-orthogonal keying employing GSRI ATCM. GSRI TC-MPSK can arbitrarily set the bandwidth expansion ratio keeping higher coding gain than the conventional pragmatic TCM scheme. By changing the modulation scheme and the bandwidth expansion ratio (coding rate), this scheme can optimize the performance according to the channel conditions. The performance evaluations by simulations on an AWGN channel and multi-path fading channels are presented. It is shown that the proposed scheme has remarkable throughput performance than that of the conventional scheme.

关键词： multi-carrier CDMA bi-orthogonal modulation Reed-Solomon code adaptive modulation and coding trellis coded modulation

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