卫星信道中高阶APSK调制的非线性失真补偿算法

针对高阶APSK调制在卫星信道中存在有记忆非线性失真的现象,提出一种联合补偿算 法,该算法充分利用APSK调制信号星座图的特点,在大幅度减小无记忆数据预失真计算量的 基础上,联合非线性均衡实现对有记忆非线性卫星信道的自适应补偿。其优点是存储量和计 算复杂度随调制阶数的增加变化很小。仿真结果表明,该算法能够达到有记忆数据预失真的 补偿性能,且最佳工作点提高0.2 dB。     

基于参量直方分布的数字信号调制识别

本文就美国针对中国产品采取特定产品保障措施第一案,从基本案情、裁决推理、裁决结果和最终结果作了归纳,并就该案的相关法律问题和潜在影响做出分析。     

Automatic control system for uniformly paving iron ore pellets

In iron and steelmaking industry, iron ore pellet qualities are crucial to end-product properties, manufacturing costs and waste emissions. Uniform pellet pavements on the grate machine are a fundamental prerequisite to ensure even heat-transfer and pellet induration successively influences performance of the following metallurgical processes. This article presents an automatic control system for uniformly paving green pellets on the grate, via a mechanism mainly constituted of a mechanical linkage, a swinging belt, a conveyance belt and a grate. Mechanism analysis illustrates that uniform pellet pavements demand the frontend of the swinging belt oscillate at a constant angular velocity. Subsequently, kinetic models are formulated to relate oscillatory movements of the swinging belt’s frontend to rotations of a crank link driven by a motor. On basis of kinetic analysis of the pellet feeding mechanism, a cubic B-spline model is built for numerically computing discrete frequencies to be modulated during a motor rotation. Subsequently, the pellet feeding control system is presented in terms of compositional hardware and software components, and their functional relationships. Finally, pellet feeding experiments are carried out to demonstrate that the control system is effective, reliable and superior to conventional methods.     

VOD点播视频流传送技术浅析

文章介绍了广电网络中VOD点播业务视频流传送技术的选择和应注意的问题等。     

基于SOA的OOK到PolSK码型转换器的研究

本文提出了一种基于SOA中的瞬时交叉相位调制(T-XPM)效应和窄带滤波器实现高速OOK到Pol SK的码型转换,建立了SOA分段模型以及滤波模型,数值模拟了40Gbit/s开关键控(OOK)码到Pol SK的转换。实验结果证明了方案的可行性。     

Novel ID-based anti-collision approach for RFID

Novel correlation ID-based (CID) anti-collision approach for RFID under the banner of the Internet of Things (IOT) has been presented in this paper. The key insights are as follows: according to the deterministic algorithms which are based on the binary search tree, we propose a method to increase the association between tags so that tags can initiatively send their own ID under certain trigger conditions, at the same time, we present a multi-tree search method for querying. When the number of tags is small, by replacing the actual ID with the temporary ID, it can greatly reduce the number of times that the reader reads and writes to tag’s ID. Active tags send data to the reader by the way of modulation binary pulses. When applying this method to the uncertain ALOHA algorithms, the reader can determine the locations of the empty slots according to the position of the binary pulse, so it can avoid the decrease in efficiency which is caused by reading empty slots when reading slots. Theory and experiment show that this method can greatly improve the recognition efficiency of the system when applied to either the search tree or the ALOHA anti-collision algorithms.     

基于幅度调制畸变Wiener模型的OOK辐射源指纹特征提取

通过分析生成On-Off Keying（OOK）信号的发射机系统的幅度调制畸变特性,阐明了OOK信号辐射源特征产生机理,建立了OOK辐射源的幅度调制畸变特性的Wiener模型,并根据信号模型应用差分进化算法完成OOK幅度畸变特性参数的估计,从而构建辐射源指纹特征完成对OOK信号辐射源的识别。仿真试验和实际数据测试表明,该算法具备OOK辐射源指纹特征提取和识别能力,对实测数据中4个OOK辐射源识别率为93%,优于基于暂态幅度特征的提取方法。     

利用累积量和似然特征的卫星单-混信号调制识别算

针对卫星通信中常用调制信号和PCMA类混叠信号的调制识别问题,提出了一种利用 高阶累积量和似然特征的识别算法。算法先对接收数据进行预处理,在此基础上提取4个高 阶累积量特征和1个似然特征,构造一个树形分类器进行调制识别。算法不需要知晓信号的 定时等先验信息,对收发载频存在的频差不敏感。仿真结果表明,算法在正常通信所需的载 噪比下具有较高的正确识别率。     

运用高阶累积量和SVM的调制自动识别

针对数字信号调制模式识别问题,提出了运用高阶累积量和二叉树支持向量机（SVM）进行 自动识别的算法。该算法首先使用信号的四阶、六阶、八阶累积量构造了5个新的分类特征 ,然后利用二叉树支持向量机分类器实现了8种信号的有效分类。仿真结果表明,该算法优 于直接多类分类支持向量机算法,在信噪比大于5 dB时,识别率达到90%以上。     

宽带卫星通信中的ACM技术

采用自适应编码调制技术(ACM)的卫星数字视频广播新标准(DVB-S2)应用到宽带卫 星通信网中,将极大提升系统吞吐量,提供更丰富的交互式业务。从实际应用的角度,分析 了ACM的控制机制并提出其编码调制方案的简化方法。仿真结果表明,在几乎不影响系统性 能的前提下,该方案可以大幅降低ACM机制的复杂度。