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).
標簽： Communications Networking Wireless
上傳時間： 2020-06-01
上傳用戶：shancjb
1.1.概述Advanced TCA（Advanced TELECOM Computing Architecture，簡稱ATCA）標準是由Compact PCI標準進一步發展而來，由于在高性能和高穩定性上有了很大的提升，因此，可以滿足未來幾年電信領域技術發展的需求。目前，ATCA標準已在公司某些產品線提出需求和引用，為配合硬件平臺和產品線即將對ATCA標準展開的全面的產品研發，結構系統部提出對ATCA標準的結構提前預研設計，避免發生類似前期產品設計中在新標準的引用上時間緊、對標準理解不透、產品缺乏實際應用檢驗就批量生產等現象而導致的一系列問題。ATCA標準中對機械結構部分的相關接口、尺寸和形式等作了詳細描述。由于本項目為結構預研項目，所以本方案僅涉及插箱部分關鍵結構形式方面的內容描述，不對實際產品應用中的結構形式作分析。1.2.目標1、對目前市場上的ATCA類產品的結構性能做對比分析；2、插箱總體結構上體現整機結構功能模塊的布局和性能實現，單板結構方面重點對起拔器性能做分析；3、滿足ATCA際準對設備散熱能力的要求；4、滿足設備在EMCESD方面的性能要求；5、體現局部功能單元的方案實現細節。
標簽： ATCA標準
上傳時間： 2022-07-04
上傳用戶：
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
上傳時間： 2022-07-08
上傳用戶：
