資源塊 (LTE下行鏈路)
外觀
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,即既有頻分復用,又有時分復用,還有空分復用。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。[1]
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,每個符號占據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占用一個資源塊,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
[編輯]- 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 – 行動網路扁平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
[編輯]- ^ Stefania Sesia, Issam Toufik and Matthew Baker, LTE – The UMTS Long Term Evolution: From Theory to Practice, (John Wiley & Sons, Ltd.), 2009, ISBN 978-0-470-69716-0.
延伸閱讀
[編輯]- 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 (頁面存檔備份,存於網際網路檔案館)", 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 Challenges(頁面存檔備份,存於網際網路檔案館)", 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
[編輯]- LTE homepage from the 3GPP website
- LTE A-Z Description (頁面存檔備份,存於網際網路檔案館) 3GPP LTE Encyclopedia
白皮書及其他技術信息
[編輯]- LTE Technology Overview and Tutorial Series including Webinars and Video presentations
- "The Long Term Evolution of 3G" on Ericsson Review, no. 2, 2005 (頁面存檔備份,存於網際網路檔案館)
- LTE technology introduction[失效連結]
- "3G Long-Term Evolution" by Dr. Erik Dahlman at Ericsson Research (頁面存檔備份,存於網際網路檔案館)
- "Long-Term 3G Evolution – Radio Access" by Dr. Stefan Parkvall at Ericsson Research (頁面存檔備份,存於網際網路檔案館)
- "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" (頁面存檔備份,存於網際網路檔案館)
- Role of Crypto in Mobile Communications "LTE Security"(頁面存檔備份,存於網際網路檔案館)
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