资源块 (LTE下行链路)

**资源块（LTE下行链路）**是LTE下行链路分配给用户的最小单位。LTE下行链路能够分配给用户的资源包括频域资源、时域资源和空域资源，即既有频分复用，又有时分复用，还有空分复用。空域资源分配是通过MIMO实现的。资源块（resource block）是包含了12个子载波（频域）并且持续一个时隙slot（时域）的一个资源组合。一个时隙长0.5毫秒。

在0.5毫秒（一个时隙）时间内，LTE下行链路能够生成7个OFDM符号，每个符号占据12个子载波。不过资源块中OFDM符号的持续时间不完全相等，第一个OFDM符号的时间稍长（通过延长OFDM符号的循环前缀CP来实现）。资源块由资源片（resource element）组成，资源片是1个子载波（频域）并且持续一个时隙slot（时域）的资源组合。

两个时隙组成一个1毫秒的子帧（subframe），10个子帧(subframe)组成一个10毫秒的帧(frame)。帧（frame）是时域资源的最大单位。

假设某个用户的信息只占用一个资源块，LTE下行链路先将用户信息数据包串并转换成12路子数据流；每个子数据流用一个子载波进行调制，一共是12个子载波；调制过程重复7次，即产生7个OFDM符号。持续的时间是0.5毫秒；最后12路子载波承载的信息通过并串转换，在空口发送出去。

## 參見
* 无线数据标准的对比
* eMBMS&nbsp;– LTE增强型广播多播服务。
* E-UTRA&nbsp;– LTE无线连接网络。
* Flat IP&nbsp;– 移动网络扁平IP架构。
* 長期演進技術
* LTE Advanced&nbsp;– LTE的昇級版。
* 系統架構演進&nbsp;– 是3GPP對於LTE無線通信標準的核心網路架構的升級計劃。
* TD-LTE (LTE TDD)&nbsp;– 由中国所开发的一种可选的LTE标准。
* 超行動寬頻&nbsp;– LTE曾经的竞争对手，从未进行过商业化。
* WiMAX&nbsp;– 同屬4G的規格。
* HSPA+ - 3GPPHSPA标准的增强版本。
* Zadoff–Chu 公式
* 下一代網路（NGN）

## 註釋

## 延伸阅读
* Erik Dahlman, Stefan Parkvall, Johan Sköld "4G&nbsp;– LTE/LTE-Advanced for Mobile Broadband", Academic Press, 2011, ISBN 978-0-12-385489-6
* Stefania Sesia, Issam Toufik, and Matthew Baker, "LTE&nbsp;– The UMTS Long Term Evolution&nbsp;– From Theory to Practice", Second Edition including Release 10 for LTE-Advanced, John Wiley & Sons, 2011, ISBN 978-0-470-66025-6
* Chris Johnson, "LTE in BULLETS ", CreateSpace, 2010, ISBN 978-1-4528-3464-1
* Erik Dahlman, Stefan Parkvall, Johan Sköld, Per Beming, "3G Evolution&nbsp;– HSPA and LTE for Mobile Broadband", 2nd edition, Academic Press, 2008,ISBN 978-0-12-374538-5
* Borko Furht, Syed A. Ahson, "Long Term Evolution: 3GPP LTE Radio And Cellular Technology", Crc Press, 2009, ISBN 978-1-4200-7210-5
* F. Khan, "LTE for 4G Mobile Broadband&nbsp;– Air Interface Technologies and Performance", Cambridge University Press, 2009
* Mustafa Ergen, "Mobile Broadband&nbsp;– Including WiMAX and LTE", Springer, NY, 2009
* H. Ekström, A. Furuskär, J. Karlsson, M. Meyer, S. Parkvall, J. Torsner, and M. Wahlqvist, "Technical Solutions for the 3G Long-Term Evolution," *IEEE Commun. Mag.*, vol. 44, no. 3, March 2006, pp.&nbsp;38–45
* E. Dahlman, H. Ekström, A. Furuskär, Y. Jading, J. Karlsson, M. Lundevall, and S. Parkvall, "The 3G Long-Term Evolution&nbsp;– Radio Interface Concepts and Performance Evaluation," *IEEE Vehicular Technology Conference (VTC) 2006 Spring*, Melbourne, Australia, May 2006
* K. Fazel and S. Kaiser, *Multi-Carrier and Spread Spectrum Systems: From OFDM and MC-CDMA to LTE and WiMAX*, 2nd Edition, John Wiley & Sons, 2008, ISBN 978-0-470-99821-2
* Agilent Technologies, "LTE and the Evolution to 4G Wireless: Design and Measurement Challenges", John Wiley & Sons, 2009 ISBN 978-0-470-68261-6
* Sajal Kumar Das, John Wiley & Sons (April 2010): "Mobile Handset Design", ISBN 978-0-470-82467-2 .
* Beaver, Paul, "What is TD-LTE?", RF&Microwave Designline, September 2011.
* Samuel C. Yang, "OFDMA System Analysis and Design", Artech House, 2010, ISBN 978-1-60807-076-3

## 外部連結

* LTE homepage from the 3GPP website
* LTE A-Z Description  3GPP LTE Encyclopedia

### 白皮书及其他技术信息

* LTE Technology Overview and Tutorial Series including Webinars and Video presentations
* "The Long Term Evolution of 3G" on Ericsson Review, no. 2, 2005 
* LTE technology introduction
* "3G Long-Term Evolution" by Dr. Erik Dahlman at Ericsson Research 
* "Long-Term 3G Evolution&nbsp;– Radio Access" by Dr. Stefan Parkvall at Ericsson Research 
* "3GPP Long-Term Evolution / System Architecture Evolution: Overview" by Ulrich Barth at Alcatel
* The 3G Long-Term Evolution&nbsp;– Radio Interface Concepts and Performance Evaluation
* LTE and the Evolution to 4G Wireless Design and Measurement Challenges&nbsp;– "LTE Security" 
* Role of Crypto in Mobile Communications "LTE Security"

* LTE Uplink Interference Modeling