Presentation on theme: "Doc.: IEEE 802.22-08/0101r0 Submission March 2008 Baowei Ji, Samsung Slide 1 Inter-BS Synchronization Accuracy and Typical Measured Delay Spread IEEE P802.22."— Presentation transcript:
doc.: IEEE /0101r0 Submission March 2008 Baowei Ji, Samsung Slide 1 Inter-BS Synchronization Accuracy and Typical Measured Delay Spread IEEE P Wireless RANs Date: Authors: Notice: This document has been prepared to assist IEEE 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 IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s 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 Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures 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 Chairhttp://standards.ieee.org/guides/bylaws/sb-bylaws.pdf Carl R. StevensonCarl 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 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at >
doc.: IEEE /0101r0 Submission March 2008 Baowei Ji, Samsung Slide 2 Abstract Section Synchronization of IEEE Base Stations with CBP, especially, Section Precise cell synchronization were reviewed in the last interim meeting. This document refers to typical measured delay spread for addressing the accuracy concern raised in the meeting.
doc.: IEEE /0101r0 Submission March 2008 Baowei Ji, Samsung Slide 3 Inter-BS Synchronization Design CDMA2000: “Base station synchronization can be achieved through several techniques including self-synchronization, radio beep, or through satellite-based systems such as GPS, Galileo, or GLONASS”* GSM, WCDMA, HDPA, LTE: no mandatory requirement e: no mandatory requirement h: GPS, if no GPS, “Synchronization with operating WirelessMAN-CX systems shall be accomplished either by use of synchronization distributed via the Coexistence Control Channel or through a Network Time Protocol (NTP) server.”**, *** : Mandatory GPS-like method, backup with over-the-air synchronization method * ** IEEE P802.16h/D4, Feb 2008 *** NTP accuracy (several to hundreds of milliseconds)
doc.: IEEE /0101r0 Submission March 2008 Baowei Ji, Samsung Slide 4 Precise cell synchronization
doc.: IEEE /0101r0 Submission March 2008 Baowei Ji, Samsung Slide 5 Typical Measured Values of RMS Delay Spread 
doc.: IEEE /0101r0 Submission March 2008 Baowei Ji, Samsung Slide 6 Another Reference In macro-cellular mobile radio, delay spreads are mostly in the range from Trms is about 100 nsec to 10 microsec. Measurements made in the U.S., indicated that delay spreads are usually less than 0.2 microsec in open areas, about 0.5 microsec in suburban areas, and about 3 micros in urban areas. Measurements in the Netherlands showed that delay spreads are relatively large in European-style suburban areas, but rarely exceed 2 microsec. However, large distant buildings such as apartment flats occasionally cause reflections with excess delays in the order of 25 microsec. Seidel and Rappaport reported delay spreads in four European cities of less than 8 microsec in macro-cellular channels, less than 2 microsec in micro-cellular channels, and between 50 and 300 ns in pico-cellular channels.
doc.: IEEE /0101r0 Submission March 2008 Baowei Ji, Samsung Slide 7 Typical Multipath Signal 
doc.: IEEE /0101r0 Submission March 2008 Baowei Ji, Samsung Slide 8 Observations Typical delay spread –Suburban area: less than 1 microsec –Urban area or mountain area: less than 10 microsec The direct path is usually strong enough for detecting the CBP preamble, and thus timing the receiving offset. In conclusion: –For typical operation area (rural, suburban), the backup method reaches synchronization accuracy of +/- 2 microsec –For urban and mountain area, the accuracy will be within +/- 10 microsec
doc.: IEEE /0101r0 Submission March 2008 Baowei Ji, Samsung Slide 9 Accuracy Requirement and Suggestion suggested +/- 2 microsec synchronization inter- BS synchronization requirement has fixed topology and no support of mobility and handover issues The primary impact is –SCW alignment –Quiet-period alignment Suggestion –With GPS-like method, BS synchronized to +/- 2 microsec –If no GPS, use backup method, BS synchronized to +/- 2 microsec most time, and +/- 10 microsec in extreme multipath situations.
doc.: IEEE /0101r0 Submission March 2008 Baowei Ji, Samsung Slide 10 References  Theodore S. Rappaport, Wireless Communications principle & practice, Prentice Hall, 1996