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
1.1.概述Advanced TCA（Advanced Telecom Computing Architecture，简称ATCA）标准是由Compact PCI标准进一步发展而来，由于在高性能和高稳定性上有了很大的提升，因此，可以满足未来几年电信领域技术发展的需求。目前，ATCA标准已在公司某些产品线提出需求和引用，为配合硬件平台和产品线即将对ATCA标准展开的全面的产品研发，结构系统部提出对ATCA标准的结构提前预研设计，避免发生类似前期产品设计中在新标准的引用上时间紧、对标准理解不透、产品缺乏实际应用检验就批量生产等现象而导致的一系列问题。ATCA标准中对机械结构部分的相关接口、尺寸和形式等作了详细描述。由于本项目为结构预研项目，所以本方案仅涉及插箱部分关键结构形式方面的内容描述，不对实际产品应用中的结构形式作分析。1.2.目标1、对目前市场上的ATCA类产品的结构性能做对比分析；2、插箱总体结构上体现整机结构功能模块的布局和性能实现，单板结构方面重点对起拔器性能做分析；3、满足ATCA际准对设备散热能力的要求；4、满足设备在EMCESD方面的性能要求；5、体现局部功能单元的方案实现细节。
标签： ATCA标准
上传时间： 2022-07-04
上传用户：
PrefaceDuring the past years, there has been a quickly rising interest in radio access technologies for providingmobile as well as nomadic and fixed services for voice, video, and data. The difference indesign, implementation, and use between Telecom and datacom technologies is also becoming moreblurred. One example is cellular technologies from the Telecom world being used for broadband dataand wireless LAN from the datacom world being used for voice-over IP.Today, the most widespread radio access technology for mobile communication is digital cellular,with the number of users passing 5 billion by 2010, which is more than half of the world’s population.It has emerged from early deployments of an expensive voice service for a few car-borne users,to today’s widespread use of mobile-communication devices that provide a range of mobile servicesand often include camera, MP3 player, and PDA functions. With this widespread use and increasinginterest in mobile communication, a continuing evolution ahead is foreseen.This book describes LTE, developed in 3GPP (Third Generation Partnership Project) and providingtrue 4G broadband mobile access, starting from the first version in release 8 and through the continuingevolution to release 10, the latest version of LTE. Release 10, also known as LTE-Advanced,is of particular interest as it is the major technology approved by the ITU as fulfilling the IMTAdvancedrequirements. The description in this book is based on LTE release 10 and thus provides acomplete description of the LTE-Advanced radio access from the bottom up.Chapter 1 gives the background to LTE and its evolution, looking also at the different standardsbodies and organizations involved in the process of defining 4G. It also gives a discussion of the reasonsand driving forces behind the evolution.Chapters 2–6 provide a deeper insight into some of the technologies that are part of LTE and itsevolution. Because of its generic nature, these chapters can be used as a background not only for LTEas described in this book, but also for readers who want to understand the technology behind othersystems, such as WCDMA/HSPA, WiMAX, and CDMA2000.Chapters 7–17 constitute the main part of the book. As a start, an introductory technical overviewof LTE is given, where the most important technology components are introduced based onthe generic technologies described in previous chapters. The following chapters provide a detaileddescription of the protocol structure, the downlink and uplink transmission schemes, and the associatedmechanisms for scheduling, retransmission and interference handling. Broadcast operation andrelaying are also described. This is followed by a discussion of the spectrum flexibility and the associated
上传时间： 2022-07-08
上传用户：
