检索结果-内蒙古大学图书馆

adaptive modulation and coding Techniques for OFDMA Systems

IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2009年第9期8卷 4876-4883页

作者： Fantacci, Romano Marabissi, Dania Tarchi, Daniele Habib, Ibrahim Univ Florence Dept Elect & Telecommun I-50139 Florence Italy CUNY City Coll Dept Elect Engn New York NY 10031 USA

The demand for high-speed services and multimedia applications anywhere and anytime has led to the rise of wireless communications. In particular, WiMAX technology is nowadays considered one of the most prominent solutions capable to provide a Broadband Wireless Access (BWA) in metropolitan areas with a simpler installation and lower cost than traditional wired alternatives. This paper deals with the proposal of efficient adaptive modulation and coding techniques to be used in WiMAX based wireless networks, that allow to improve network performance in the case of Non Line-of-Sight communications, which are typical in urban environments. Through these techniques it is possible to switch the modulation order and coding rate in order to better match the channel conditions, and, hence, obtaining better performance both in terms of error probability and data throughput.

关键词： OFDMA adaptive modulation and coding IEEE 802.16 broadband wireless access WiMAX

来源：评论

学校读者我要写书评

暂无评论

adaptive modulation and coding using deep recurrent neural network

引用

TELECOMMUNICATION SYSTEMS 2022年第4期81卷 615-623页

作者： Mohammadvaliei, Sadegh Sebghati, Mohammadali Zareian, Hassan IRIB Univ Engn Fac Dept Informat & Commun Technol ICT Tehran Iran

adaptive modulation and coding (AMC) is a promising technique to increase the average spectral efficiency of communication links. This research proposes a novel AMC method based on a supervised deep learning approach to maximize the average spectral efficiency of OFDM wireless systems while the bit error rate (BER) remains under a predefined threshold. The proposed method consists of a one-dimensional convolutional network that performs feature extraction and a long short-term memory network that learns the behavior of the channel. Input features are the magnitudes and phases of the estimated channel frequency response in the pilot subcarriers and signal-to-noise ratio. Datasets of various fading channel responses were generated using WINNER II. The proposed method was compared with previous methods based on different criteria, including average spectral efficiency, BER, the accuracy of predictions, the average delay of each prediction, and model complexity. The simulation results confirmed the superiority of the proposed AMC method.

关键词： adaptive modulation and coding Link adaptation Deep neural network OFDM

来源：评论

学校读者我要写书评

暂无评论

adaptive modulation and coding With LDPC Codes and Retransmission for Ultraviolet Communication

IEEE PHOTONICS JOURNAL

引用

IEEE PHOTONICS JOURNAL 2024年第3期16卷 1页

作者： Long, Fei Tang, Jingyin Li, Lingfeng Chen, Jingyang Gong, Chen Xu, Zhengyuan Univ Sci & Technol China Sch Informat Sci & Technol CAS Key Lab Wireless Opt Commun Hefei 230027 Peoples R China

To adapt to different transmission power and distances, we design a rate-compatible transmission protocol to realize different transmission rates for ultraviolet (UV) communication. We have designed ensembles based on low-density parity-check (LDPC) codes, incorporating various code lengths and rates working under different channel conditions. Furthermore, the direct sequence spreading technique is adopted to obtain different channel codes working in weaker channel conditions. Through simulating the frame error rate (FER) performance across various signal and background radiation intensities, we obtain a table of switching thresholds for channel coding under distinct channel conditions. Different from that for radio-frequency (RF) communication with only one parameter of signal-to-noise ratio (SNR), the switching threshold table is constructed based on the combination of two parameters for UV Communication, the signal intensity and background radiation intensity. We also propose adaptive coding with hybrid automatic retransmission requests based on the combination of signal intensity and background intensity. It is verified through simulation that our designed system shows larger throughput under varying channel conditions compared with channel coding with a fixed rate in UV Communication.

关键词： Wireless UV optical communication adaptive modulation and coding hybrid automatic retransmission request low-density parity-check

来源：评论

学校读者我要写书评

暂无评论

adaptive modulation and coding for Interference Alignment With Imperfect CSIT

引用

IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2014年第9期13卷 5264-5273页

作者： Taki, Mehrdad Rezaee, Mohsen Guillaud, Maxime Univ Isfahan Dept Elect Engn Esfahan 84156 Iran Univ Paderborn D-33098 Paderborn Germany Vienna Univ Technol Inst Telecommun A-1040 Vienna Austria

In this paper, interference alignment (IA) based on imperfect channel state information (CSI) is investigated. As the accuracy of the CSI at the transmitter side is crucial for IA, we analyze the statistics of the imperfect CSI and design an adaptive scheme based on the available imperfect CSI. We consider a multiple-input-multiple-output (MIMO) interference channel where the transmit and receive spaces are determined by IA. Using practical modulation schemes, we consider the maximization of a weighted sum of the average rates provided that a certain set of bit-error-rate and power constraints is satisfied by dynamically adapting coding, modulation, and power settings. The problem in such a general form is intractable. Therefore, we resort to some approximations and provide simulations to show the accuracy of the approximations in the regimes with practical interest.

关键词： Interference alignment link adaptation imperfect CSI adaptive modulation and coding

来源：评论

学校读者我要写书评

暂无评论

adaptive modulation and coding for Underwater Acoustic OTFS Communications Based on Meta-Learning

引用

IEEE COMMUNICATIONS LETTERS 2024年第8期28卷 1845-1849页

作者： Jing, Lianyou Dong, Chaofan He, Chengbing Shi, Wentao Wang, Han Zhou, Yi Northwestern Polytech Univ Ocean Inst Suzhou 215400 Jiangsu Peoples R China Dalian Univ Technol Sch Informat & Commun Engn Dalian 116024 Liaoning Peoples R China Northwestern Polytech Univ Sch Marine Sci & Technol Xian 710072 Shaanxi Peoples R China Air Force Engn Univ Informat & Nav Coll Xian 710051 Shaanxi Peoples R China

This letter proposes an adaptive modulation and coding (AMC) scheme based on deep learning for underwater acoustic (UWA) communications. To achieve good communication performance in fast time-varying UWA channels, the proposed AMC scheme is implemented on the orthogonal time-frequency space (OTFS) modulation system. We design an end-to-end deep convolutional neural network (CNN) to capture the channel features and determine the optimal modulation and coding scheme. Additionally, we utilize a meta-learning algorithm to address environment mismatch in real-world UWA applications. This algorithm effectively adapts the CNN model from a given UWA environment to a new UWA environment with only a small amount of data. The performance of the proposed scheme is verified through real-world measured channels. Simulation results demonstrate that the proposed method outperforms existing machine learning-based AMC and fixed modulation and coding schemes in various UWA scenarios, offering better communication throughput and stronger learning capabilities.

关键词： Underwater acoustic communications adaptive modulation and coding orthogonal time frequency space convolutional neural network meta-learning Underwater acoustic communications adaptive modulation and coding orthogonal time frequency space convolutional neural network meta-learning

来源：评论

学校读者我要写书评

暂无评论

adaptive modulation and coding for Performance Enhancement of Vehicular Communication

引用

WIRELESS PERSONAL COMMUNICATIONS 2022年第1期123卷 195-214页

作者： Shukla, Devesh Prakash, Arun Tripathi, Rajeev Motilal Nehru Natl Inst Technol Allahabad Elect & Commun Engn Dept Prayagraj 211004 India

With the advancements and increase in the transportation system in the current scenario, making transports intelligent is an important aspect for enhancing the safety, security and related commercial applications. Vehicular ad-hoc network has been evolved for the implementation of intelligent transportation systems. Vehicular scenario comprising of multipath fading, interference, dispersion and mobility distort the communication among the vehicles and between vehicles and surroundings. This work implements adaptive modulation and coding technique in the existing vehicular communication transmission process. Simulations were carried out for different transmission schemes with different code rate over several wireless channels for varying signal-to-noise ratio for performance evaluation. The results of this simulation testify that the proposed technique serves better than fixed transmission scheme in terms of bit error rate and spectral efficiency. adaptive modulation together with turbo coding shows an approximate gain of 10 dB signal-to-noise ratio relative to fixed schemes.

关键词： Vehicular communication IEEE 802 11p adaptive modulation and coding Turbo codes

来源：评论

学校读者我要写书评

暂无评论

adaptive modulation and coding for QoS-based Femtocell Resource Allocation with Power Control

Adaptive Modulation and Coding for QoS-based Femtocell Resou...

引用

IEEE Global Communications Conference (GLOBECOM)

作者： Hatoum, Rima Hatoum, Abbas Ghaith, Alaa Pujolle, Guy Univ Paris 06 LIP6 4 Pl Jussieu F-75005 Paris France Lebanese Univ EDST Beirut Lebanon

ISBN: (纸本)9781479935123

Nowadays, LTE-based femtocell technology is a promising solution offering high-speed services, enhanced indoor coverage and increased system capacity. In such multi-user wireless communication systems, intelligently allocating resources is the substantial aim towards interference mitigation and enhancing power and spectral efficiencies. In this paper, we propose a joint power and channel allocation with adaptive modulation and coding (AMC) technique for downlink OFDMA-based LTE system, namely AMC-QRAP. As trade-off between distributed and centralized architectures, we consider a clustered network architecture. Users differentiation is taken into account to ensure Quality of Service (QoS) guarantee where premium High Priority HP users and best effort BE users are served by the network. Our allocation problem is resolved as an optimization model using linear programming. Extensive simulations prove that our proposal outperforms different techniques in the literature and considerably improve two previously proposed methods QP-FCRA and Q-FCRA. We consider different metrics for performance evaluation such as spectral efficiency, throughput satisfaction rate, user outage and transmission power.

关键词： adaptive modulation and coding Power Control Resource Allocation QoS OFDMA-Femtocell

来源：评论

学校读者我要写书评

暂无评论

adaptive modulation and coding with multicodes over Nakagami fading channels

Adaptive modulation and coding with multicodes over Nakagami...

引用

IEEE Wireless Communications and Networking Conference

作者： Kwan, R Leung, C Univ British Columbia Dept Elect & Comp Engn Vancouver BC V6T 1Z4 Canada

ISBN: (纸本)0780389662

adaptive modulation and coding (AMC) has been adopted in the 3GPP standard in order to improve spectral efficiency. In order to increase the granularity of the adaptation and to provide higher bit rates, multicode transmission is employed. Since the use of AMC requires knowledge of the channel state, the accuracy of this information is important. In practice, errors in estimating the channel state are inevitable, resulting in performance degradation. In this paper, the average bit rate performance of AMC with multicodes is studied for a CDMA system experiencing Nakagami fading and channel estimation errors. The results are obtained in terms of the generalized Marcum Q-function. Numerical results are provided to illustrate the performance degradations due to inaccuracies in estimating the channel.

关键词： adaptive modulation and coding multicode imperfect channel estimation CDMA Nakagami fading

来源：评论

学校读者我要写书评

暂无评论

adaptive modulation and coding in WiMAX System for Optimum Image Transmission

Adaptive Modulation and Coding in WiMAX System for Optimum I...

引用

Conference on Innovative Technologies in Intelligent Systems and Industrial Applications

作者： Beitmashal, Ehsan Ashourian, Mohsen Kazemi, Hooshang Islamic Republ Azad Univ Najafabad Esfahan Iran Islamic Republ Azad Univ Majlesi Esfahan Iran

ISBN: (纸本)9781424428861

adaptive modulation and coding (AMC) is one of the main advantage of the WiMAX system in Broadband Wireless Access (BWA) applications. The system changes modulation and coding to provide high quality of service. This feature is especially attractive for services like on demand video and image transmission. The physical layer of system monitors the channel condition and estimating Signal to Noise Ratio (SNR) of received signals to change adaptively. In this paper, we evaluate the system performance for image transmission. We use Peak Signal to Noise Ratio (PSNR) factor in AMC and compare it with a classical system that uses signal to noise ratio for a pilot random signal.

关键词： adaptive modulation and coding WiMAX PSNR

来源：评论

学校读者我要写书评

暂无评论

adaptive modulation and coding for the IEEE 802.15.3c High Speed Interface Physical Layer Mode

引用

Mediterranean Conference on Information and Communication Technologies (MedCT)

作者： Azza, Mohammed Amine El Yahyaoui, Moussa El Moussati, Ali Natl Sch Appl Sci Signals Syst & Informat Proc Oujda Morocco

ISBN: (纸本)9783319303017;9783319302997

adaptive modulation and coding (AMC) is a technique that allows the adjustment of modulation and coding based on the quality of the transmission link, to achieve a transmission with higher data rate and better spectral efficiency. The purpose of this paper is to study the influence of AMC on the High Speed Interface Physical layer (HSI PHY) mode of the IEEE 802.15.3c standard. For this we have created a Simulink model representing the schema of the IEEE 802.15.3c transmitter/receiver with an algorithm which allows adaptation in terms of modulation and coding of the transmitter according to the link in accordance with a predefined script.

关键词： IEEE 802.15.3c adaptive modulation and coding OFDM 60 GHz

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：