When 3GPP started standardizing the IMS a few years ago, most analysts expected the number of IMS deploymentsto grow dramatically as soon the initial IMS specifications were ready (3GPP Release 5 was functionallyfrozenin the first half of 2002and completedshortly after that). While those predictions have proven to be too aggressive owing to a number of upheavals hitting the ICT (Information and Communications Technologies) sector, we are now seeing more and more commercial IMS-based service offerings in the market. At the time of writing (May 2008), there are over 30 commercial IMS networks running live traffic, addingup to over10million IMS users aroundthe world; the IMS is beingdeployedglobally. In addition, there are plenty of ongoing market activities; it is estimated that over 130 IMS contracts have been awarded to all IMS manufacturers. The number of IMS users will grow substantially as these awarded contracts are launched commercially. At the same time, the number of IMS users in presently deployed networks is steadily increasing as new services are introduced and operators running these networks migrate their non-IMS users to their IMS networks.
标签： Multimedia Subsystem The IMS 3G IP
上传时间： 2020-06-01
上传用户：shancjb
Wireless communications has become a field of enormous scientific and economic interest. Recent success stories include 2G and 3G cellular voice and data services (e.g., GSM and UMTS), wireless local area networks (WiFi/IEEE 802.11x), wireless broadband access (WiMAX/IEEE 802.16x), and digital broadcast systems (DVB, DAB, DRM). On the physical layer side, traditional designs typically assume that the radio channel remains constant for the duration of a data block. However, researchers and system designers are increasingly shifting their attention to channels that may vary within a block. In addition to time dispersion caused by multipath propagation, these rapidly time-varying channels feature frequency dispersion resulting from the Doppler effect. They are, thus, often referred to as being “doubly dispersive.”
标签： Time-Varying Channels
上传时间： 2020-06-01
上传用户：shancjb
During the past three decades, the world has seen signifi cant changes in the telecom- munications industry. There has been rapid growth in wireless communications, as seen by large expansion in mobile systems. Wireless communications have moved from fi rst-generation (1G) systems primarily focused on voice communications to third-generation (3G) systems dealing with Internet connectivity and multi-media applications. The fourth-generation (4G) systems will be designed to connect wire- less personal area networks (WPANs), wireless local area networks (WLANs) and wireless wide-area networks (WWANs).
标签： Communications Networking Wireless
上传时间： 2020-06-01
上传用户：shancjb
This chapter provides extensive coverage of existing mobile wireless technologies. Much of the emphasis is on the highly anticipated 3G cellular networks and widely deployed wireless local area networks (LANs), as the next-generation smart phones are likely to offer at least these two types of connectivity. Other wireless technologies that either have already been commercialized or are undergoing active research and standardization are introduced as well. Because standardization plays a crucial role in developing a new technology and a market, throughout the discussion standards organizations and industry forums or consortiums of some technologies are introduced. In addition, the last section of this chapter presents a list of standards in the wireless arena.
标签： Networking Wireless Complete
上传时间： 2020-06-01
上传用户：shancjb
This book paves the path toward fourth generation (4G) mobile communica- tion by introducing mobility in heterogeneous IP networks with both third generation (3G) and wireless local area networks (WLANs), which is seen as one of the central issues in the becoming 4G of telecommunications networks and systems. This book presents a thorough overview of 3G networks and standards and discusses interworking and handover mechanisms between WLANs and the Universal Mobile Telecommunication System (UMTS).
标签： Wireless towards WLANs WPANs 4G
上传时间： 2020-06-01
上传用户：shancjb
LSM6DS3 是系统级封装的 3D 数字加速度计和 3D 数字陀螺仪，具有数字 I2C/SPI 串口标准输出，在组合正常工作模式下 6 轴功耗 0.9 mA，在组合高性能工作模式下 6 轴功耗 1.25mA （数据输出速率可达到 1.6 kHz）。由于陀螺仪和加速度计均具有超低噪声性能，始终具有低功耗特性，并结合了高传感精度，因此能够为客户提供最佳运动体验。此外，加速度计具有智能的休眠到唤醒 （活动）和返回休眠 （不活动）功能，具有先进的节电能力。
上传时间： 2021-11-13
上传用户：wangshoupeng199
接触Silvaco TCAD仿真软件已经有很长时间了，这期间还熟悉了一下ISE TCAD。学习的过程中，老师、师兄姐和同学给了我极大的帮助。这本书的主旨就是希望提供一些对于Silvaco仿真的可资借鉴的经验。学习和使用Silvaco的时候各人的视角会不一样，虽然这本书只是介绍一些常用的仿真，例句也有限，但因为流程控制和语法都有相通的地方，完全可以参照本书和手册的说明灵活地建立仿真以及仿真一些本书未提及的特性。写本书的另一个动力是想体验一下IAT在排版书籍上和word的不同。经过这次编排觉得各有优缺点。IZTX对排图片和表格这些浮动元素很费力。我在排此书的时候经常遇到图片和表格按照自动方式排的位置很差，和文字内容脱节很远，为此不得不处理图片，有时还将表格拆开等。如果各位遇到很脱节的地方还请见谅。LTX的使用需要有很强的耐心和探索精神，也可以说是牺牲精神。不管是MS Office还是ITEX，总的目的是想内容通顺，阅读起来舒服，用什么工具就是“八仙过海，各显神通”了。
上传时间： 2021-11-27
上传用户：qingfengchizhu
经过总体构成功能的分析后，接下来就可以根据各构成功能模块进行对应的总体设计处理。主要包括两个方面：运行流程分析；核心处理模块分析。
标签： C语言
上传时间： 2021-12-02
上传用户：
广和通是中国首家A股上市的物联网无线模组企业。致力于将可靠、便捷、安全、智能的无线通信解决方案普及至每一个物联网应用场景，丰富智慧生活。广和通提供创新的5G、4G、3G、2G、NB-IoT、LTE-M、智能、车规级无线通信模组及物联网应用一站式无线通信解决方案 。广和通拥有全球1000多名员工，产品及服务遍及100多个国家。
标签： 物联网
上传时间： 2021-12-26
上传用户：
1. 引言2. 概述3.3.1 100Mbps 以上的边缘速率3.3.2 99.999% 高可靠性和≤ 1ms 的超低时延3.3.3 1 个连接/ 平方米3.3.4 其他3.3.5 小结4.1.1 高频组网传播损耗与穿透损耗大，室外覆盖室内难4.1.2 无源分布式天线系统演进难、综合损耗大、互调干扰大3.1 5G 三大业务类型3.2 室内5G 业务及特征3.3 室内5G 业务对网络的需求4.2 多样化的业务要求网络具备更大的弹性容量4.3 行业应用要求网络具备极高可靠性4.4 四代共存网络及新业务发展要求网络具有高效运维、智能运营能力4.5 小结5.1 组网策略： 高中低频分层组网，提供更大容量5.2 MIMO 选择策略：标配4T4R，提供更好的用户体验5.3 方案选择策略：大容量数字化方案是必然选择5.4 容量策略：弹性容量，灵活按需满足业务需求5.5 可靠性策略：面向5G 业务的可靠性设计5.6 部署策略：端到端数字化部署，奠定网络运维和运营的基础5.7 网络运维策略：可视化运维，实现室内5G 网络可管可控5.8 网络运营策略：基于网络运营平台，支撑室内5G 网络智能运营5.9 小结
上传时间： 2022-01-30
上传用户：qdxqdxqdxqdx
