共查询到20条相似文献，搜索用时 203 毫秒
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提出一种基于数字波束形成(DBF)的机载SAR自适应干扰抑制方案.该方案根据干扰的方向,在成像的过程中,实时地调整接收波束方向图,使得主波束对准成像区域,同时在干扰方向形成零陷.为了在成像过程中,只对波束进行有限次调整,采用了宽零陷波束形成算法.并对该方案的性能进行分析,仿真表明了该方案的可行性和有效性. 相似文献
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正交频分复用（OFDM）技术是当今无线通信领域中的研究与应用热点,它具有抗多径衰落、频谱利用率高、采用自适应调制等优点,被普遍认为是宽带无线接入和第四代移动通信系统中的关键技术之一.本文从基本频率复用策略出发,基于频率复用策略的研究方法和现状,提出了一种新型的提高频率利用率的频率复用策略,并对其在OFDM系统中的发展趋势进行了展望. 相似文献
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DBF天线安装后,一般不具备可机械旋转的常规测试条件.研究DBF天线方向图的间接测试问题,提出一种基于波束扫描的测试方法,给出其测试原理和测试流程.针对波束宽度、副瓣水平和波束指向等天线主要参数,用仿真比对该方法与常规方法的测试结果和误差.在DBF天线方向图正常和异常两种情况下,两种方法可得到相近的仿真测试结果,证明间接测试方法的有效性. 相似文献
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协作通信运用于多用户正交频分复用网络（MU—OFDM）是一种对抗无线信道衰落和提高吞吐量的有效方法,被广泛运用于下一代无线通信网络。文章在当前信道情况（CSI）已知的情况,提出了一种基于提高用户信道容量和系统公平性的资源分配策略。并在此基础上给出了实现这个算法的4个步骤。仿真结果说明该算法能够在保证公平性的前提下大幅度提高系统吞吐量,并且在吞吐量上超过了一些已有的算法。 相似文献
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针对阵列信号中部分自适应信号处理问题,提出了一种新的基于平滑阵列的降维方法. 该方法将全阵列平滑处理,通过分割成相互重叠的子阵达到降维的目的. 该波束形成器使用了两级加权的结构. 根据方向图相乘原理,天线方向图是两级加权矢量独立产生的方向图的乘积,此波束形成器可以等效为一种空域滤波器的级联形式. 通过大量的计算机仿真验证了此方法的有效性和优越性. 相似文献
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针对低轨道(LEO)通信卫星的特点,进行星载多波束天线的系统级分析和规划.首先,对天线体制选择多波束天线的原因进行了论述.基于卫星覆盖范围的指标,进行了7波束等覆盖面积方案下波束指标的计算,给出了波束宽度、夹角等系统指标.然后对阵列天线方案进行了详细论述.最后对波束形成方案以及复用方案进行了设计和分析. 相似文献
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本文针对嵌入式手持设备中无线通信模块数据传输速率较低的问题,提出一种基于WLAN模块进行数据传输的方法.文章给出了BGW211模块的硬件连接图,并基于Linux操作系统开发了设备驱动程序.测试结果证明设计方案完全可行. 相似文献
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提出了基于八分弧的对一般圆锥曲线扫描转换算法。该算法中利用八分弧将圆锥曲线分成八个区域进行扫描转换,在每个八分弧中确定算法跟踪的方向,使用梯度的分量来确定运动的方向从而画八分弧,并以椭圆为例给出了相应的算法过程。 相似文献
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《Journal of The Franklin Institute》2021,358(18):10213-10231
Orbit Angular Momentum (OAM) is a potential candidate for next-generation short-distance line-of-sight wireless communication, it is assumed that the channels associated with different OAM modes are orthogonal. When there are misalignments between transmitter and receiver arrays, the assumption is incorrect. In this paper, we propose the methods to estimate the array misalignment values in the OAM-based communication system for Uniform Circular Array (UCA) in transmitter and receiver. It is shown that, when the pilot signals are transmitted in a single or all OAM modes, the absolute value of the received signal can be approximated by the polynomial functions of misalignment angle. By solving these functions, the misalignment angle can be estimated. The proposed methods are theoretically analyzed and tested for OAM Index Modulation (OAM-IM)-based communication system, The obtained results indicate that the proposed methods improve the OAM-IM based communication system in the presence of array misalignments problem. 相似文献
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为了解决在非固定地点开展特殊气象服务的问题,提出了基于车载式自动气象站、无线通信网络的移动气象台的概念,介绍了安阳市移动气象台的基本配制,阐述了移动气象台系统功能设计方案以及和以CDMA无线通信技术以及Web技术为主的技术实现方法。 相似文献
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本文提出了基于ZigBee技术的面向农作物的无线传感器网络监测系统的设计方案,其中硬件子系统包括四大部分：处理器模块、无线通信模块、传感器模块和电源模块;软件子系统涉及开发平台Tiny0S系统、CC2420驱动设计、串口和内网通信程序设计和传感器数据采集模块设计。系统具有良好的灵活性、可维护性和可扩展性,同时系统模块化、开放式的结构使系统具有良好的可移植性。 相似文献
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混沌粒子群算法在WSN覆盖优化中的应用 总被引：1，自引：0，他引：1
研究WSN覆盖优化方面的问题,提高无线传感网络通讯效率。针对无线传感网络节点分布不均匀或者节点失效时,WSN覆盖区域会出现重叠或者指定区域没有被覆盖,造成无线传感网络通讯效率下降的问题,提出了利用一种混沌粒子群算法,根据无线传感网络相关参数和条件建立数学模型,利用优化处理方式对其进行优化,提高了通讯效率。实验证明,利用混沌粒子群算法进行WSN覆盖优化,可以提高无线传感网络优化效率,取得了令人满意的效果。 相似文献
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本文提出基于无线传感器网络技术的煤矿安全监测系统,阐述了无线传感器网络体系设计及节点的硬件和软件设计,选择了基于IEEE802.15.4标准的ZigBee技术作为无线传感器网络的通信方案,充分利用无线传感器网络的优点,实现对井下各种环境及生产参数全方位、实时监测,尽可能地减少煤矿安全生产隐患,更好的为安全生产服务。 相似文献
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To retrieve the information from the serious distorted received signal is the key challenge of communication signal processing. The chaotic baseband communication promises theoretically to eliminate the inter-symbol interference (ISI), however, it needs complicated calculation, if it is not impossible. In this paper, a genetic algorithm support vector machine (GA-SVM) based symbol detection method is proposed for chaotic baseband wireless communication system (CBWCS), by this way, treating the problem from a different viewpoint, the symbol decoding process is converted to be a binary classification through GA-SVM model. A trained GA-SVM model is used to decode the symbols directly at the receiver, so as to improve the bit error rate (BER) performance of the CBWCS and simplify the symbol detection process by removing the channel identification and the threshold calculation process as compared to that using the calculated threshold to decode symbol in the traditional methods. The simulation results show that the proposed method has better BER performance in both the static and time-varying wireless channels. The experimental results, based on the wireless open-access research platform, indicate that the BER of the proposed GA-SVM based symbol detection approach is superior to the other counterparts under a practical wireless multipath channel. 相似文献
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《Journal of The Franklin Institute》2017,354(11):4457-4480
Due to the hopeful application of gathering information from unreachable position, wireless sensor network creates an immense challenge for data routing to maximize the communication with more energy efficiency. In order to design the energy efficient routing, the optimization based clustering protocols are more preferred in wireless sensor network. In this paper, we have proposed competent optimization based algorithm called Fractional lion (FLION) clustering algorithm for creating the energy efficient routing path. Here, the proposed clustering algorithm is used to increase the energy and lifetime of the network nodes by selecting the rapid cluster head. In addition, we have proposed multi-objective FLION clustering algorithm to develop the new fitness function based on the five objectives like intra-cluster distance, inter-cluster distance, cluster head energy, normal nodes energy and delay. Here, the proposed fitness function is used to find the rapid cluster centroid for an efficient routing path. Finally, the performance of the proposed clustering algorithm is compared with the existing clustering algorithms such as low energy adaptive clustering hierarchy (LEACH), particle swarm optimization (PSO), artificial bee colony (ABC) and Fractional ABC clustering algorithm. The results proved that the lifetime of the wireless sensor nodes is maximized by the proposed FLION based multi-objective clustering algorithm as compared with existing protocols. 相似文献
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3G移动通信系统可以满足用户随时随地更快速的传输多媒体应用与实时性服务的需求,而IEEE的802.11无线网络则可以为用户提供涵盖范围较小、高速的数据传输环境。因此将两种传输技术结合为用户提供快速无缝接入的通信能力,并能在这两种传输技术间快速的切换,有着重大的现实意义。考虑到无线传输的环境中,用户对移动性的需求较高,因此本文以3GPP制定的3G与WLAN整合架构为基础,提出一种基于移动IPv6的异构网络快速切换策略,以减少用户在移动过程中所造成的服务中断和数据包丢失问题。 相似文献
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Jianjun Bai Hongye Su Jinfeng Gao Tao Sun Zhengguang Wu 《Journal of The Franklin Institute》2012,349(7):2420-2430
The problem of modeling and stabilization of a wireless network control system (NCS) is considered in this paper, where packet loss and time delay exist simultaneously in the wireless network. A discrete-time switched system with time-varying delay model is first proposed to describe the system closed by a static state feedback controller. A sufficient criteria for the discrete-time switched system with time-varying delay to be stable is proposed, based on which, the corresponding state feedback controller is obtained by solving a set of linear matrix inequalities (LMIs). Numerical examples show the effectiveness of the proposed method. 相似文献
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针对偏远地区水情数据远程监测的实际需求,文章进行了基于zigbee协议和CDMA通信技术的远程数据采集传输系统的设计开发。以支持zigbee协议的芯片CC2530来构建传感器节点和中心节点,以CDMA无线通信模块构建能与internet进行数据传输的网关。传感器节点采用星型拓扑结构组成无线传感网络后,采集数据传给中心节点,再通过ARM处理器驱动CDMA模块实现数据的远程传输。该监测系统低功耗、易组网、易安装,适合大区域的远程无线实时监测。 相似文献