資源塊 (LTE下行鏈路)

資源塊（LTE下行鏈路）是LTE下行鏈路分配給用戶的最小單位。LTE下行鏈路能夠分配給用戶的資源包括頻域資源、時域資源和空域資源，即既有頻分複用，又有時分複用，還有空分複用。空域資源分配是通過MIMO實現的。資源塊（resource block）是包含了12個子載波（頻域）並且持續一個時隙slot（時域）的一個資源組合。一個時隙長0.5毫秒。
在0.5毫秒（一個時隙）時間內，LTE下行鏈路能夠生成7個OFDM符號，每個符號佔據12個子載波。不過資源塊中OFDM符號的持續時間不完全相等，第一個OFDM符號的時間稍長（通過延長OFDM符號的循環前綴CP來實現）。資源塊由資源片（resource element）組成，資源片是1個子載波（頻域）並且持續一個時隙slot（時域）的資源組合。
兩個時隙組成一個1毫秒的子幀（subframe），10個子幀(subframe)組成一個10毫秒的幀(frame)。幀（frame）是時域資源的最大單位。
假設某個用戶的信息只佔用一個資源塊，LTE下行鏈路先將用戶信息數據包串並轉換成12路子數據流；每個子數據流用一個子載波進行調製，一共是12個子載波；調製過程重複7次，即產生7個OFDM符號。持續的時間是0.5毫秒；最後12路子載波承載的信息通過並串轉換，在空口發送出去。

**參見**
 無線數據標準的對比- eMBMS – LTE增強型廣播多播服務。- E-UTRA – LTE無線連接網絡。- Flat IP – 移動網絡扁平IP架構。- 長期演進技術- LTE Advanced – LTE的昇級版。- 系統架構演進 – 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) – 由中國所開發的一種可選的LTE標準。- 超行動寬頻 – LTE曾經的競爭對手，從未進行過商業化。- WiMAX – 同屬4G的規格。- HSPA+ - 3GPPHSPA標準的增強版本。- Zadoff–Chu 公式- 下一代網路（NGN）

**註釋**

**延伸閱讀**
 Erik Dahlman, Stefan Parkvall, Johan Sköld "4G – LTE/LTE-Advanced for Mobile Broadband", Academic Press, 2011, ISBN 978-0-12-385489-6- Stefania Sesia, Issam Toufik, and Matthew Baker, "LTE – The UMTS Long Term Evolution – 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 date=20210225081357 ", CreateSpace, 2010, ISBN 978-1-4528-3464-1- Erik Dahlman, Stefan Parkvall, Johan Sköld, Per Beming, "3G Evolution – 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 – Air Interface Technologies and Performance", Cambridge University Press, 2009- Mustafa Ergen, "Mobile Broadband – 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. 38–45- E. Dahlman, H. Ekström, A. Furuskär, Y. Jading, J. Karlsson, M. Lundevall, and S. Parkvall, "The 3G Long-Term Evolution – 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 Challengesdate=20190710181420 ", 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 date=20210401064707  3GPP LTE Encyclopedia

**白皮書及其他技術信息**
  LTE Technology Overview and Tutorial Series including Webinars and Video presentations-  "The Long Term Evolution of 3G" on Ericsson Review, no. 2, 2005 date=20160304204831 -  LTE technology introductionbot=InternetArchiveBot -  "3G Long-Term Evolution" by Dr. Erik Dahlman at Ericsson Research date=20210507045602 -  "Long-Term 3G Evolution – Radio Access" by Dr. Stefan Parkvall at Ericsson Research date=20210505221516 -  "3GPP Long-Term Evolution / System Architecture Evolution: Overview" by Ulrich Barth at Alcatel-  The 3G Long-Term Evolution – Radio Interface Concepts and Performance Evaluation-  LTE and the Evolution to 4G Wireless Design and Measurement Challenges – "LTE Security" date=20210404052312 -  Role of Crypto in Mobile Communications "LTE Security"date=20110928092611 -  LTE Uplink Interference Modeling date=20131103042230