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为了提高第3代移动通信技术在无线接入领域的竞争力,3GPP提出了第3代移动通信的长期演进计划,即LTE。本文介绍了引入3GPPLTE目地以及它的目标和需求,重点研究了上行链路中的几个关键技术,最后对LTE的发展趋势进行了讨论。 相似文献
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随机接入技术是LTE协议栈MAC层的功能中十分重要的一项技术。在LTE中,随机接入的主要目的是上行定时同步校正,用户功率调整和用户资源需求的申请。文章为了实现LTE协议栈MAC层随机访问过程,重点研究了MAC层协议,分别提出实现随机访问过程的方案和测试仿真平台的搭建方法。文章详细描述了随机接入的流程、有限自动状态机的设计原理以及具体实现方法,为了提高LTE协议栈的性能,文章提出了零拷贝技术。使用两台PC机做了仿真实验,得到了基于竞争模式下的随机访问过程实现的结果。 相似文献
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正研究内容VoLTE即Voice over LTE,它是一种基于LTE和IMS的IP数据传输技术,能够在LTE网络上把语音与数据业务进行独立承载,并且以支持多样性的多媒体业务以及多种接入的IMS语音业务为基础。由于VoLTE可向用户提供更高质量、更低时延的服务,因此VoLTE技术作为LTE中快速发展的技术,需要持续对其发展进行跟踪,分析,提前 相似文献
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《科学中国人》2017,(2)
LTE(Long Term Evolution)是继第三代移动通信之后国际上主流的新一代移动通信标准,能够提供比3G更高的网络性能和更优的用户享受。功率控制作为无线通信系统中的一项基本技术,用于补偿无线信道的衰落影响,使得信号能够以比较适合的功率到达接收机。本文研究分析了Android平台的系统架构和组件模型,并且在此基础上,与TD-LTE功率控制过程相结合,实现了基于Android平台TD-LTE功率控制过程虚拟仿真技术应用设计。系统实现了对TD-LTE的基本知识的介绍,并能够在不同信道情况下计算功率控制值,还通过动画演示的方式,使用户了解TD-LTE的功率控制过程。 相似文献
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本文对移动通信各业务系统接入IP专网的方案进行了介绍,同时也提出了业务服务质量要求、可靠性和安全性的解决方案,并介绍了3G、NGN网络的融合趋势,以及未来IP承载网络的发展方向。 相似文献
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随着人们对移动通信系统的各种需求与日俱增,我国第四代移动通信已经开始投入商用,与3G移动通信服务相比,4G技术更为复杂,其特点主要有：高速率、技术发展以数字宽带技术为主、灵活性较强、兼容性好、用户共存性、业务的多样性;较好的技术基础、随时随地的移动接入、自治的网络结构。本文介绍了第四代移动通信系统及其特点,4G互联网应用,以及新一轮科技创新发展前景。 相似文献
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通过分析数字电视点播业务的发展态势及相关的技术背景,并结合目前广播电视网络的特点,提出了一套用于数字电视视频点播的用户接入系统的设计思想及其实现方式。该系统利用HFC网络作为上行点播信号的传输信道,数字电视用户可以使用电视遥控器与点播系统进行交互。汇聚管理部分主要根据频道资源有限的具体情况,提出了一种汇聚点播的思想,提高了整个系统服务质量。在用户点播成功之后,为了视频服务器响应用户的点播要求、播放用户点播的节目,下发控制指令让机顶盒接收点播的相应内容,设计了播出子系统。经过分析,系统性能良好、运行稳定,达到了预期的设想。 相似文献
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在LTE网络中,用户附着机制是LTE业务实现的一项关键技术,但是复杂的网络环境影响LTE用户的正常附着。根据实际运营中遇到的用户附着问题,在深入分析问题原因的基础上,提出了相应的解决方案,并取得了良好的效果。 相似文献
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<正>名词解释:LTE:是3G与4G技术之间的一个过渡,是3.9G的全球标准,它改进并增强了3G的空中接入技术。WIMAX:一种新兴的宽带无线接入技术,能提供面向互联网的高速连接。 相似文献
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This study examines characteristics that relate to lead userness in using business mobile services. From a large dataset of 2306 business decision-makers, the study identifies 205 lead users who are ahead of the majority in using business mobile services, while for the majority (n = 2101), business mobile services mainly supplement desktop and laptop computers. The authors test a binary logistic regression model in which individual technology readiness, sociodemographic variables, Internet use, and perceived importance of digital touchpoints predict lead userness in relation to business mobile services. The results show that job level is a highly significant predictor for lead userness in a work-related context, with senior management and entrepreneurs having the greatest likelihood for the use of business mobile services. Innovativeness and the perceived importance of mobile applications and social media also serve as positive predictors, while the perceived importance of websites and email result in a negative effect. The findings further suggest that the odds of being a lead user decrease by 2 percent per additional year of age, and that the odds of men is over 1.4 times greater than the odds of women. 相似文献
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针对目前移动网络认证安全情况,介绍了指纹识别的原理,通过构建指纹识别算法,结合RSA公钥加密算法和分布式运算,为网络节点提供了安全认证方案。实现了一种改进的网络身份认证方案。分析表明该方案具有较高的安全性,该体系具有更强的认证成功率和可靠性。 相似文献
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Nadia Jimenez Sonia San-Martin Nuria Puente 《The Journal of High Technology Management Research》2019,30(1):15-26
The mobile technology involves an unexplored world of doing business and consumer behavioral change that constitutes a revolution in the application of technologies to marketing. A key factor in the adoption of mobile commerce is the compatibility that the consumer perceives with his/her life. Given that the research on compatibility with mobile purchases made so far treats it as an antecedent of adoption, this pioneer research studies the influencing role of two more personal factors (self-efficacy and innovativeness) and two factors more related to the shopping (involvement and perceived entertainment). The model was tested using PLS with information from 583 Mexican mobile buyers. Our results show a positive effect of innovativeness, involvement and perceived entertainment on compatibility. On the contrary, self-efficacy does not seem to influence the perception of compatibility of mobile shopping with consumer life. This work has important implications for the practice of professionals dedicated to mobile commerce. 相似文献
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Users increasingly use mobile devices to engage in social activity and commerce, enabling new forms of data collection by firms and marketers. User privacy expectations for these new forms of data collection remain unclear. A particularly difficult challenge is meeting expectations for contextual integrity, as user privacy expectations vary depending upon data type collected and context of use. This article illustrates how fine-grained, contextual privacy expectations can be measured. It presents findings from a factorial vignette survey that measured the impact of diverse real-world contexts (e.g., medical, navigation, music), data types, and data uses on user privacy expectations. Results demonstrate that individuals’ general privacy preferences are of limited significance for predicting their privacy judgments in specific scenarios. Instead, the results present a nuanced portrait of the relative importance of particular contextual factors and information uses, and demonstrate how those contextual factors can be found and measured. The results also suggest that current common activities of mobile application companies, such as harvesting and reusing location data, images, and contact lists, do not meet users’ privacy expectations. Understanding how user privacy expectations vary according to context, data types, and data uses highlights areas requiring stricter privacy protections by governments and industry. 相似文献
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《Journal of The Franklin Institute》2022,359(11):5354-5384
This paper focuses on the energy-time optimal control of wheeled mobile robots undergoing point-to-point transitions in an obstacles free space. Two interchangeable models are used to arrive at the necessary conditions for optimality. The first formulation exploits the Hamiltonian, while the second formulation considers the first variation of the augmented cost to derive the necessary conditions for optimality. Jacobi elliptic functions are shown to parameterize the closed form solutions for the states, control and costates. Analysis of the optimal control reveal that they are constrained to lie on a cylinder whose circular cross-section is a function of the weight penalizing the relative costs of time and energy. The evolving optimal costates for the second formulation are shown to lie on the intersection of two cylinders. The optimal control for the wheeled mobile robot undergoing point-to-point motion is also developed where the linear velocity is constrained to be time-invariant. It is shown that the costates are constrained to lie on the intersection of a cylinder and an extruded parabola. Numerical results for various point-to-point maneuvers are presented to illustrate the change in the structure of the optimal trajectories as a function of the relative location of the terminal and initial states. 相似文献
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Telecommunications services are for long subject to privacy regulations. At stake are traditionally: privacy of the communication and the protection of traffic data. Privacy of the communication is legally founded. Traffic data subsume under the notion of data protection and are central in the discussion. The telecommunications environment is profoundly changing. The traditionally closed markets with closed networks change into an open market with open networks. Within these open networks more privacy sensitive data are generated and have to be exchanged between growing numbers of parties. Also telecommunications and computer networks are rapidly being integrated and thus the distinction between telephony and computing disappears. Traditional telecommunications privacy regulations are revised to cover internet applications. In this paper telecommunications issues are recalled to aid the on-going debate. Cellular mobile phones have recently be introduced. Cellular networks process a particular category of traffic data namely location data, thereby introducing the issue of territorial privacy into the telecommunications domain. Location data are bound to be used for pervasive future services. Designs for future services are discussed and evaluated for their impact on privacy protection.Parts of this paper have been presented at Ubicomp 2002 in Goteborg and E-CAP 2003 in Glasgow. 相似文献