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.”
標(biāo)簽： Time-Varying Channels
上傳時(shí)間： 2020-06-01
上傳用戶：shancjb
Today wireless is becoming the leader in communication choices among users. It is not anymore a backup solution for nomadic travellers but really a newmoodnaturallyusedeverywhereevenwhenthewiredcommunicationsare possible. Many technologies evolve then continuously, changing the telecom- munication world. We talk about wireless local area networks (WLANs), wire- less personal area networks (WPANs), wireless metropolitan area networks (WMANs), wireless wide area networks (WWANs), mobile ad hoc networks (MANETs), wireless sensor networks (WSNs) and mesh networks. Since we can find today a multitude of wireless technologies we decided to group a numberofcomplementarytechnologiesintoonedocumenttomakeiteasierfor areadertounderstandsomeofthetechnicaldetailsofeachmedia.
標(biāo)簽： TM Bluetooth Zigbee Wi-Fi WImax and
上傳時(shí)間： 2020-06-01
上傳用戶：shancjb
Notwithstanding its infancy, wireless mesh networking (WMN) is a hot and growing field. Wireless mesh networks began in the military, but have since become of great interest for commercial use in the last decade, both in local area networks and metropolitan area networks. The attractiveness of mesh networks comes from their ability to interconnect either mobile or fixed devices with radio interfaces, to share information dynamically, or simply to extend range through multi-hopping.
標(biāo)簽： Multi-hop Networks WImax WiFi Mesh LTE and
上傳時(shí)間： 2020-06-01
上傳用戶：shancjb
所設(shè)計(jì)的多頻段小型化天線結(jié)構(gòu)新穎，性能指標(biāo)優(yōu)越，與當(dāng)前國(guó)內(nèi)外研究的大多數(shù)同類(lèi)天線相比保持較小體積，在多頻、寬頻工作頻段上也保持較強(qiáng)的競(jìng)爭(zhēng)力。其中所設(shè)iMonopole，780MHz-1010MHz和1630MHz3900MHz，在高頻頻段上的提升相當(dāng)明顯，與大多數(shù)同類(lèi)天線相比提升超過(guò)100%，除了覆蓋GSM，UMTS，LTE的頻段外，還覆蓋WImax的頻段，為未來(lái)5G通信的多頻段融合發(fā)展提供有力支撐；所設(shè)計(jì)多頻段小型化PIFA天線，工作頻段為680MHz980MHz和1665MHz-2755MHz，覆蓋GSM，UMTS，LTE所需的所有頻段，同時(shí)該天線的小型化指標(biāo)憂異，其輻射貼片部分的尺寸僅為33mm x mm0.8mm，在當(dāng)前國(guó)內(nèi)外同類(lèi)天線中具有相當(dāng)強(qiáng)的競(jìng)爭(zhēng)力。這兩款天線結(jié)構(gòu)簡(jiǎn)單，加工成本低，十分適用于5G移動(dòng)通信移動(dòng)終端中。最后，設(shè)計(jì)一款超寬帶微帶天線。所設(shè)計(jì)的超寬帶微帶天線利用新型倒置E型槽，獲得了超寬帶性能，工作頻段覆蓋27.6GHz-33.2GHz.采用新的債電方式一半圓漸進(jìn)饋電，不僅可以改善天線的輻射特性，還能降低阻抗匹配的難度，進(jìn)而一定程度上簡(jiǎn)化了天線的設(shè)計(jì)難度。在天線輻射貼片開(kāi)有圓角矩形槽，大大的改善了天線的阻抗特性，進(jìn)一步優(yōu)化了天線的輻射特性，保證了天線在整個(gè)煩段內(nèi)輻射方向圖的穩(wěn)定性。天線加工簡(jiǎn)單、成本低，非常適用于5G移動(dòng)通信的大規(guī)模組網(wǎng)。
標(biāo)簽： 5G 移動(dòng)通信 天線
上傳時(shí)間： 2022-06-20
上傳用戶：
5G，第五代移動(dòng)通信技術(shù)，也是4G之后的延伸，目前正在研究中。目前還沒(méi)有任何電信公司或標(biāo)準(zhǔn)訂定組織（像3GPP，WImax論壇及ITU-R）的公開(kāi)規(guī)格或官方文件有提到5G。按照業(yè)內(nèi)初步估計(jì)，包括5G在內(nèi)的未來(lái)無(wú)線移動(dòng)網(wǎng)絡(luò)業(yè)務(wù)能力的提升將在3個(gè)維度上同時(shí)進(jìn)行：1）通過(guò)引入新的無(wú)線傳輸技術(shù)將資源利用率在4G的基礎(chǔ)上提高10倍以上；2）通過(guò)引入新的體系結(jié)構(gòu)（如超密集小區(qū)結(jié)構(gòu)等）和更加深度的智能化能力將整個(gè)系統(tǒng)的吞吐率提高25倍左右；3）進(jìn)一步挖掘新的頻率資源（如高頻段、毫米波與可見(jiàn)光等），使未來(lái)無(wú)線移動(dòng)通信的頻率資源擴(kuò)展4倍左右.5G有以下特點(diǎn)：1）5G研究在推進(jìn)技術(shù)變革的同時(shí)將更加注重用戶體驗(yàn)，網(wǎng)絡(luò)平均吞吐速率、傳輸時(shí)延以及對(duì)虛擬現(xiàn)實(shí)、3D、交互式游戲等新興移動(dòng)業(yè)務(wù)的支撐能力等將成為衡量5G系統(tǒng)性能的關(guān)鍵指標(biāo).2）與傳統(tǒng)的移動(dòng)通信系統(tǒng)理念不同，5G系統(tǒng)研究將不僅僅把點(diǎn)到點(diǎn)的物理層傳輸與信道編譯碼等經(jīng)典技術(shù)作為核心目標(biāo)，而是從更為廣泛的多點(diǎn)、多用戶、多天線、多小區(qū)協(xié)作組網(wǎng)作為突破的重點(diǎn)，力求在體系構(gòu)架上尋求系統(tǒng)性能的大幅度提高.3）室內(nèi)移動(dòng)通信業(yè)務(wù)已占據(jù)應(yīng)用的主導(dǎo)地位，5G室內(nèi)無(wú)線覆蓋性能及業(yè)務(wù)支撐能力將作為系統(tǒng)優(yōu)先設(shè)計(jì)目標(biāo)，從而改變傳統(tǒng)移動(dòng)通信系統(tǒng)“以大范圍覆蓋為主、兼顧室內(nèi)"的設(shè)計(jì)理念.4）高頻段頻譜資源將更多地應(yīng)用于5G移動(dòng)通信系統(tǒng)，但由于受到高頻段無(wú)線電波穿透能力的限制，無(wú)線與有線的融合、光載無(wú)線組網(wǎng)等技術(shù)將被更為普遍地應(yīng)用.5）可“軟”配置的5G無(wú)線網(wǎng)絡(luò)將成為未來(lái)的重要研究方向，運(yùn)營(yíng)商可根據(jù)業(yè)務(wù)流量的動(dòng)態(tài)變化實(shí)時(shí)調(diào)整網(wǎng)絡(luò)資源，有效地降低網(wǎng)絡(luò)運(yùn)營(yíng)的成本和能源的消耗.
標(biāo)簽： 5g 移動(dòng)通信
上傳時(shí)間： 2022-06-21
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
標(biāo)簽： 4g 移動(dòng)通信
上傳時(shí)間： 2022-07-08
上傳用戶：
VIP專(zhuān)區(qū)-嵌入式/單片機(jī)編程源碼精選合集系列（109）資源包含以下內(nèi)容：1. 包括匯編和c++編寫(xiě)的萬(wàn)年歷.2. FIFO（先進(jìn)先出隊(duì)列）通常用于數(shù)據(jù)的緩存和用于容納異步信號(hào)的頻率或相位的差異。本FIFO的實(shí)現(xiàn)是利用 雙口RAM 和讀寫(xiě)地址產(chǎn)生模塊來(lái)實(shí)現(xiàn)的.FIFO的接口信號(hào)包括異步的寫(xiě)時(shí)鐘（wr_clk）和讀.3. Analog signals are represented by 64 bit buses. They are converted to real and from real representa.4. 該文件為lpc2106 ARM7在THREDX操作系統(tǒng)下的啟動(dòng)代碼.5. 該代碼為時(shí)鐘芯片PCF8563的控制程序.6. 此代碼位PIC單片機(jī)的PID控溫程序.7. threadx技術(shù)手冊(cè).8. 一個(gè)關(guān)于fat32系統(tǒng)文件的說(shuō)明,對(duì)了解fat32文件系統(tǒng)系統(tǒng)結(jié)構(gòu)很有用.9. 典型的開(kāi)發(fā)模型有：①瀑布模型(waterfall model)；②漸增模型/演化/迭代(incremental model)；③原型模型(prototype model)；④螺旋模型(spiral m.10. zigbee協(xié)議中.11. 三菱FX系列PLC與PC機(jī)通過(guò)編程口通訊的地址轉(zhuǎn)換軟件,非常的使用!.12. 文章講述了類(lèi)似于PDOP值的描述整周模糊度精度的指標(biāo)因子。對(duì)于整周模糊度的判斷具有重要意義。.13. 講述了如何對(duì)主引導(dǎo)扇區(qū)進(jìn)行備份和恢復(fù).14. LED驅(qū)動(dòng)電路實(shí)例。配具體的電路圖供大家參考使用.15. Pcb初級(jí)教程.16. 嵌入式內(nèi)存數(shù)據(jù)庫(kù)系統(tǒng)eXtremeDB用戶指南.17. 對(duì)引導(dǎo)區(qū)的學(xué)駐病毒進(jìn)行了剖析.18. LPC2146 的USB 開(kāi)發(fā).19. 非常詳細(xì)步進(jìn)電機(jī)控制原理圖.20. C++ GUI Programming with Qt 4一書(shū)中的第一章源碼.21. C++ GUI Programming with Qt 4一書(shū)中的chap02源碼.22. C++ GUI Programming with Qt 4一書(shū)中的chap03源碼.23. C++ GUI Programming with Qt 4一書(shū)中的chap05源碼.24. C++ GUI Programming with Qt 4一書(shū)中的chap06源碼.25. C++ GUI Programming with Qt 4一書(shū)中的chap07源碼.26. C++ GUI Programming with Qt 4一書(shū)中的chap8源碼.27. C++ GUI Programming with Qt 4一書(shū)中的chap9源碼.28. 具有無(wú)線網(wǎng)路功能下載至嵌入式開(kāi)發(fā)平臺(tái)上用的.o黨 driver.29. ADI DSP ADSP-BF561原裝開(kāi)發(fā)板的PCB圖,非常難得! POWERPCB 5.0可以打開(kāi)..30. ADI TS201 原裝系統(tǒng)板PCB圖, 此PCB圖是用POWERPCB 5.0畫(huà)的, 直接導(dǎo)入既可打開(kāi), 目前做相控陣?yán)走_(dá),3G 基站,WImax基站等均采用ADSP-TS201..31. ADI DSP BF561 系統(tǒng)板原理圖,只有PDF格式的,.32. 利用89C52開(kāi)發(fā)的.33. PCtoLCD2002完美版 取字模軟件.34. lm317 計(jì)算工具.35. 這是一個(gè)非常不錯(cuò)的12864液晶串口程序.36. 嵌入式系統(tǒng)開(kāi)發(fā)原理、工具及過(guò)程 值得推薦.37. minigui－－面向?qū)崟r(shí)嵌入式系統(tǒng)的圖形用戶界面。此文檔介紹了miniguide體系結(jié)構(gòu)。.38. 該源碼與書(shū)本配套.39. 《EVC高級(jí)編程及其應(yīng)用開(kāi)發(fā)》一書(shū)的全部源代碼.40. 將MATLAB窗口畫(huà)在VC的GUI上 輕松實(shí)現(xiàn)用MATLAB和VC畫(huà)圖.
標(biāo)簽： 網(wǎng)絡(luò)通信協(xié)議
上傳時(shí)間： 2013-06-12
上傳用戶：eeworm
VIP專(zhuān)區(qū)-嵌入式/單片機(jī)編程源碼精選合集系列（150）資源包含以下內(nèi)容：1. ＴＣＲＴ５０００光電傳感器.2. 關(guān)于PLC控制的資料,內(nèi)容全面,供參考用..3. 這是設(shè)計(jì)好并調(diào)試通過(guò)了的智能負(fù)載電路原理圖和PCB板圖.4. I2C 總線8 位遠(yuǎn)程I/O 擴(kuò)展口芯片PCF8574 的原理與應(yīng)用.5. 基于ADI 公司的blackfin芯片的通用中斷框架程序.6. 基于ADI blackfin 的DMA 描述符方式的程序。便于你理解這種獨(dú)特的dma搬送方式.7. 基于ADI blackfin的異常處理程序.8. 基于ADI BLACKFIN的jbig壓縮和解壓縮程序.9. max531的驅(qū)動(dòng)程序,采用SPI接收方式.經(jīng)驗(yàn)證,完全正確..10. 關(guān)于自制C8051單片機(jī)編程器的文檔.11. 國(guó)內(nèi)某測(cè)溫系統(tǒng)信號(hào)處理處理板的代碼.12. PIC系列單片機(jī)典型應(yīng)用程序集: 17c42.13. PIC系列單片機(jī)典型應(yīng)用程序集: 24lc.14. PIC系列單片機(jī)典型應(yīng)用程序集: 93c46.15. PIC系列單片機(jī)典型應(yīng)用程序集: 93c.16. PIC系列單片機(jī)典型應(yīng)用程序集: b16tobcd.17. PIC系列單片機(jī)典型應(yīng)用程序集: bcd.18. PIC系列單片機(jī)典型應(yīng)用程序集: BCD2BIN.19. PicoBlaze 處理器 SPI Flash 編程器的詳細(xì)資料.20. 簡(jiǎn)易灰度調(diào)制.21. LCD ST7787 QVGA 屏 的 驅(qū) 動(dòng).22. PICC學(xué)習(xí).23. 這些都是常用的通信設(shè)備的電路原理圖.24. 調(diào)試好的LCDTV方案.25. 串口中斷＿niosII.c SOPC UART!.26. NIOSII I2C源程序.27. C語(yǔ)言規(guī)范,在寫(xiě)程序可以避免一些不必要的錯(cuò)誤.28. 10分鐘學(xué)會(huì)PLD,仿真.29. ARM平臺(tái)下的數(shù)字音頻AGC處理源代碼 采用EP9302,對(duì)數(shù)字音頻進(jìn)行AGC處理.30. VESA and Industry Standard and Guidelines for Computer Display Monitor Timing Version 1.0.31. 基于89s52單片機(jī).32. 基于51系列單片機(jī)的開(kāi)機(jī)計(jì)數(shù)實(shí)驗(yàn).33. 基于WImax中ofdm在vxworks的仿真代碼.34. C8051F系列單片機(jī)測(cè)溫程序.35. 5615十位DA轉(zhuǎn)換芯片C的原程序.36. 縫紉機(jī)主機(jī)板測(cè)試程序； 使用嵌入式系統(tǒng)。.37. ATmega48-88-168_中文說(shuō)明書(shū).38. nios鍵盤(pán)數(shù)碼管驅(qū)動(dòng)芯片HD7279驅(qū)動(dòng)程序.39. C+++GUI Programming with Qt4 的源碼.40. Philip ISP1181芯片驅(qū)動(dòng).
上傳時(shí)間： 2013-04-15
上傳用戶：eeworm
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