doc.: IEEE /0570r0 Submission Zander LEI, I2R Singapore December 2007 Slide 1 Beacon Structure Requires Shorter Sensing Windows for the IEEE Standard 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 /0570r0 Submission Zander LEI, I2R Singapore December 2007 Slide 2 Abstract To detect and decode beacons, WRAN requires two sensing windows (short and long) which are greater than 5.1ms and 100+ ms respectively based on current draft. An alternative beacon structure is in this contribution to shorten required windows to 3.3ms and 49.2ms respectively. The submission follows the agreed procedure for resolving comments 472 and provides detailed changes to the current beacon design.

doc.: IEEE /0570r0 Submission Zander LEI, I2R Singapore December 2007 Slide 3 Introduction Beacon Burst Has 3 Critical Parts –Synchronization sequence: Detect existence of beacon burst –Index: Indicate when/where Payload starts –Payload : Contains Addr, Location, Channel Maps, Security etc. 2 Steps (using 2 sensing windows) to Detect 3 Parts 1.Using Short Sensing Window Detect Synchronization sequence Detect Index to Schedule Long sensing window 2.Using Long Sensing Window Detect Payload

doc.: IEEE /0570r0 Submission Zander LEI, I2R Singapore December 2007 Slide 4 Current Burst-Beacon Design

doc.: IEEE /0570r0 Submission Zander LEI, I2R Singapore December 2007 Slide 5 Current Burst-Beacon Design Sync=15b Index (inc. parity)=15b … PPDU = 120 bytes = 99.9 ms … Sync Index (inc. parity) Rsv =2b Rsv 4 Bytes = 3.33 ms 1 byte = ms 1 bit = ms Chip rate = kcps Bit rate = kbps I-channel Q-channel

doc.: IEEE /0570r0 Submission Zander LEI, I2R Singapore December 2007 Slide 6 I-channel Sensing Windows Required 48+1 = 49 bit = 5.1 ms window SyncIndexR Short Sensing Window SyncIndexR PPDU = 120 bytes = 99.9 ms Long Sensing Window Scheduled window w/ knowledge of starting point = = 100+ ms window or 5.1 ms window Sync Q-channel

doc.: IEEE /0570r0 Submission Zander LEI, I2R Singapore December 2007 Slide 7 Problems Required Short Sensing Window is too long ~ 5.1 ms –A shorter sensing window is desired –Can be shorten to 3.3 ms! Required Long Sensing window is too long > 100 ms –Minimum 11 WRAN frames needed! –Can be shorten to 5 frames!

doc.: IEEE /0570r0 Submission Zander LEI, I2R Singapore December 2007 Slide 8 Proposed Beacon Structure Index (41) Sync Index (40) Sync Index (39) Superframe period PPDU (contains MAC beacon frame) I-channel Q-channel … Sync Index (39) (b) Index (0) Sync Index (39) Index (0) Sync Burst Q-channel I-channel Inter-device communication period PPDU (contains MAC beacon frame) … Sync ANP RX period Superframe period Sync Index (39) (a)

doc.: IEEE /0570r0 Submission Zander LEI, I2R Singapore December 2007 Slide 9 Proposed Beacon Structure PPDU Q = 59 bytes = 49.1 ms Sync=15b Index (inc. parity)=15b … PPDU I = 59 bytes = 49.1 ms … < 2 Bytes = 1.56 ms Sync Index Sync Index No zero padding requiredNo Rsv bits required Proposed No content change Sync=15b Index (inc. parity)=15b … PPDU = 120 bytes = 99.9 ms … Sync Index (inc. parity) Rsv =2b Rsv 4 Bytes = 3.33 ms Current I-channel Q-channel I-channel Q-channel

doc.: IEEE /0570r0 Submission Zander LEI, I2R Singapore December 2007 Slide 10 PPDU MSF2 = 51 bytesMSF1 + FEC= 34MSF3=33 bytes Proposed Physical PPDU Current PPDU MSF2 = 51 bytesMSF1 + FEC= 34MSF3=33 bytes Proposed Logical PPDU I-channel Q-channel PPDU I = 59 bytes PPDU Q = 59 bytes No content change Bit Mapping 34 (MSF1) + 25 (MSF2) =59 bytes 26 (MSF2)+33 (MSF3) =59 bytes

doc.: IEEE /0570r0 Submission Zander LEI, I2R Singapore December 2007 Slide 11 I-channel New Short Sensing Windows Required 48+1 = 49 bit = 5.1 ms window SyncIndexR Short Sensing Window SyncIndexR or 5.1 ms window Sync Index I-channel Current Proposed Sync Index Sync Index 31+1 = 32 bit = 3.3 ms window Q-channel

doc.: IEEE /0570r0 Submission Zander LEI, I2R Singapore December 2007 Slide 12 I-channel New Long Sensing Windows Required Payload = 120 bytes = 99.9 ms Long Sensing Window Scheduled window w/ knowledge of starting point = = 100 ms window Current Payload Q = 59 bytes = 49.1 ms Payload I = 59 bytes = 49.1 ms I-channel Q-channel Scheduled window w/ knowledge of starting point = = 49.2 ms window Proposed

doc.: IEEE /0570r0 Submission Zander LEI, I2R Singapore December 2007 Slide 13 Capture of Sync with a Pair of Short Windows with Delay T PPDU Q … PPDU I T1 = 75 bytes = 62.4 ms Tp= 59 bytes = 49.1 ms Sync 0 39 Tw 62.6 ms > T0 > 53.8 ms PPDU Q … PPDU I Sync 0 41 … Sync 0 41 T = T0 +k* Tframe or Tframe = ms A sensing device has the flexibility to choose any value in {0, 1, 2 …} as k T=T0   ensure one of short window capture Sync Sync 40 Sync 39 Sync 40 Sync 39 T2= 2*Tburst = 3.1 ms Tw=3.3 ms Tw Tburst = 15 bit = 1.56 ms Tw  T1 > T0 -Tw+2*Tburst =T0-0.2 T  T0 > Tburst+Tp+T2=53.8 ms

doc.: IEEE /0570r0 Submission Zander LEI, I2R Singapore December 2007 Slide 14 Performance Same error rate performance –Sync: same sequence, chip rate, spreading factor –Index: same block size, modulation and FEC –PPDU: same # of info bytes, modulation and FEC

doc.: IEEE /0570r0 Submission Zander LEI, I2R Singapore December 2007 Slide 15 Summary Enhancement to Beacon Transmission –Shorter short window: 3.3 ms (vs 5.1 ms) –Shorter long window: 49.2 ms or 5 WRAN frame (vs 11 frame) –No performance discount –No significant change to the current draft