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ofdma

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  • 1. January 2005 Doc.: IEEE802.22-05-0005r0 Tutorial on Multi Access OFDM (OFDMA) Technology IEEE P802.22 Wireless RANs Date: 2005-01-04 Authors: Name Company Address Phone email Eli Sofer Runcom 2 Hachoma St., 75655 +972 3 9528440 [email protected] Technologies Rishon Lezion, Israel Yossi Segal Runcom 2, achoma St. 75655 +972 3 952 8440 [email protected] Technologies Rishon Lezion, Israel Notice: This document has been prepared to assist IEEE 802.22. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEEs name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEEs sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802.22. Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures http://standards.ieee.org/guides/bylaws/sb-bylaws.pdf including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair Carl R. Stevenson as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE 802.22 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at [email protected] > Submission Slide 1 Eli Sofer, RuncomRuncom Technologies Ltd. 1
  • 2. January 2005 Doc.: IEEE802.22-05-0005r0 Abstract The contribution presents a tutorial on Multi Access OFDM (OFDMA) technology which has been endorsed in leading standards such as- ETSI DVB-RCT and IEEE802.16a,d and 16e. Essential parameters of UpLink and DownLink and simulation results are presented. System capabilities and advantages are also discussed. The tutorial could offer an insight and understanding of OFDMA technology to be considered as a candidate for WRAN system Submission Slide 2 Eli Sofer, RuncomRuncom Technologies Ltd. 2
  • 3. January 2005 Doc.: IEEE802.22-05-0005r0 Tutorial on Multi Access OFDM (OFDMA) Technology Eli Sofer Runcom Technologies Ltd Submission Slide 3 Eli Sofer, RuncomRuncom Technologies Ltd. 3
  • 4. January 2005 Doc.: IEEE802.22-05-0005r0 Contents OFDMA System Architecture Illustrated Example OFDMA System Properties Coverage and Capacity Submission Slide 4 Eli Sofer, RuncomRuncom Technologies Ltd. 4
  • 5. January 2005 Doc.: IEEE802.22-05-0005r0 OFDMA System Architecture Submission Slide 5 Eli Sofer, RuncomRuncom Technologies Ltd. 5
  • 6. January 2005 Doc.: IEEE802.22-05-0005r0 Duplexing Technique FDD/TDD Multiple Access Method TDMA/OFDMA OFDM Symbols allocated by TDMA Sub-Carriers within an OFDM Symbol allocated by OFDMA Diversity Frequency, Time, Code (CPE and BS), Space Time Coding, Antenna Array Submission Slide 6 Eli Sofer, RuncomRuncom Technologies Ltd. 6
  • 7. January 2005 Doc.: IEEE802.22-05-0005r0 Duplexing - Principles FDD (Frequency Division Duplexing ) Uses One Frequency for the DownLink, and a Second Frequency for the UpLink. TDD (time Division Duplexing) Uses the same frequency for the Downlink and the Uplink. In any configuration the access method is OFDMA/TDMA . DownLink UpLink FDD F1 - Frequency band F2 - Frequency band DownLink UpLink TDD F1 - Frequency band F1 - Frequency band Submission Slide 7 Eli Sofer, RuncomRuncom Technologies Ltd. 7
  • 8. January 2005 Doc.: IEEE802.22-05-0005r0 OFDMA-TDMA Principles Using OFDMA/TDMA, Sub Channels are allocated in the Frequency Domain, and OFDM Symbols allocated in the Time Domain. t TDMA TDMAOFDMA m N Submission Slide 8 Eli Sofer, RuncomRuncom Technologies Ltd. 8
  • 9. January 2005 Doc.: IEEE802.22-05-0005r0 DownLink OFDMA Symbol Sub-Channel Data Carriers Symbol Pilots Total Frequency Band Guard Band Guard Band Submission Slide 9 Eli Sofer, RuncomRuncom Technologies Ltd. 9
  • 10. January 2005 Doc.: IEEE802.22-05-0005r0 DownLink Specification Burst Structure is defined from one Sub-channel in the Frequency domain and n OFDMA time symbols in the time domain, each burst consists of N data modulated carriers. Adaptive Modulation and Coding per Sub-Channel in the Down-Link Forward APC controlling (+6dB) (-6dB) digital gain on the transmitted Sub-Channel Supporting optional Space Time Coding employing Alamouti STC. Supporting optional Adaptive Array. Submission Slide 10 Eli Sofer, RuncomRuncom Technologies Ltd. 10
  • 11. January 2005 Doc.: IEEE802.22-05-0005r0 Example- DownLink Specification FFT size : 2048 Guard Intervals : , 1/8, 1/

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