December 2007 doc IEEE 802 22 -07 0570

December 2007 doc. : IEEE 802. 22 -07/0570 r 0 Beacon Structure Requires Shorter Sensing Windows for the IEEE 802. 22. 1 Standard Date: 2007 -12 -24 Authors: 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 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 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 patcom@iee. org. Submission 1 Zander LEI, I 2 R Singapore

December 2007 doc. : IEEE 802. 22 -07/0570 r 0 Abstract • To detect and decode 802. 22. 1 beacons, WRAN requires two sensing windows (short and long) which are greater than 5. 1 ms and 100+ ms respectively based on current draft. • An alternative beacon structure is in this contribution to shorten required windows to 3. 3 ms and 49. 2 ms respectively. • The submission follows the agreed procedure for resolving comments 472 and provides detailed changes to the current beacon design. Submission 2 Zander LEI, I 2 R Singapore

December 2007 doc. : IEEE 802. 22 -07/0570 r 0 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 • Submission Detect Payload 3 Zander LEI, I 2 R Singapore

December 2007 doc. : IEEE 802. 22 -07/0570 r 0 Current Burst-Beacon Design Submission 4 Zander LEI, I 2 R Singapore

December 2007 doc. : IEEE 802. 22 -07/0570 r 0 Current Burst-Beacon Design 4 Bytes = 3. 33 ms I-channel Q-channel • • Submission Sync=15 b … Index (inc. Rsv parity)=15 b =2 b … Sync Index (inc. Rsv parity) PPDU = 120 bytes = 99. 9 ms 1 byte = 0. 8325 ms 1 bit = 0. 104 ms Chip rate = 76. 873 kcps Bit rate = 9. 6091 kbps 5 Zander LEI, I 2 R Singapore

December 2007 doc. : IEEE 802. 22 -07/0570 r 0 Sensing Windows Required Short Sensing Window 48+1 = 49 bit = 5. 1 ms window I-channel Sync Index R Sync or Index R Sync 5. 1 ms window Long Sensing Window Scheduled window w/ knowledge of starting point = 99. 9 + 0. 1 = 100+ ms window Q-channel Submission PPDU = 120 bytes = 99. 9 ms 6 Zander LEI, I 2 R Singapore

December 2007 doc. : IEEE 802. 22 -07/0570 r 0 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! Submission 7 Zander LEI, I 2 R Singapore

December 2007 doc. : IEEE 802. 22 -07/0570 r 0 Proposed Beacon Structure Superframe period Inter-device communication period I-channel Q-channel Sync … Sync RX period Index (0) Index (39) Sync Burst Sync PPDU (contains MAC beacon frame) ANP Index (39) (a) Superframe period I-channel Q-channel Sync Index (39) … Sync Index (0) Sync Index (41) PPDU (contains MAC beacon frame) Index (40) Index (39) (b) Submission 8 Zander LEI, I 2 R Singapore

December 2007 doc. : IEEE 802. 22 -07/0570 r 0 Proposed Beacon Structure 4 Bytes = 3. 33 ms I-channel Sync=15 b … Index (inc. Rsv parity)=15 b =2 b Q-channel … Sync Index (inc. Rsv parity) PPDU = 120 bytes = 99. 9 ms Current < 2 Bytes = 1. 56 ms No Rsv bits required I-channel Sync=15 b Sync Q-channel Index (inc. parity)=15 b Index No content change Submission …… No zero padding required Sync PPDU I = 59 bytes = 49. 1 ms Index PPDU Q = 59 bytes = 49. 1 ms Proposed 9 No content change Zander LEI, I 2 R Singapore

December 2007 doc. : IEEE 802. 22 -07/0570 r 0 PPDU I-channel MSF 1 + FEC= 34 MSF 2 = 51 bytes MSF 3=33 bytes Current PPDU No content change Proposed Logical PPDU MSF 1 + FEC= 34 Bit Mapping MSF 2 = 51 bytes 34 (MSF 1) + 25 (MSF 2) =59 bytes I-channel PPDU I = 59 bytes Q-channel MSF 3=33 bytes Bit Mapping PPDU Q = 59 bytes 26 (MSF 2)+33 (MSF 3) =59 bytes Proposed Physical PPDU Submission 10 Zander LEI, I 2 R Singapore

December 2007 doc. : IEEE 802. 22 -07/0570 r 0 New Short Sensing Windows Required Short Sensing Window 48+1 = 49 bit = 5. 1 ms window I-channel Sync Index R Current Sync or Index R Sync 5. 1 ms window 31+1 = 32 bit = 3. 3 ms window I-channel Sync Proposed Q-channel Submission Index 11 Index Zander LEI, I 2 R Singapore

December 2007 doc. : IEEE 802. 22 -07/0570 r 0 New Long Sensing Windows Required Long Sensing Window Scheduled window w/ knowledge of starting point = 99. 9 + 0. 1 = 100 ms window Payload = 120 bytes = 99. 9 ms I-channel Current Scheduled window w/ knowledge of starting point = 49. 1 + 0. 1 = 49. 2 ms window I-channel Payload I = 59 bytes = 49. 1 ms Proposed Q-channel Submission Payload Q = 59 bytes = 49. 1 ms 12 Zander LEI, I 2 R Singapore

December 2007 doc. : IEEE 802. 22 -07/0570 r 0 Capture of Sync with a Pair of Short Windows with Delay T Tframe = 114. 7 ms T 1 = 75 bytes = 62. 4 ms Tp= 59 bytes = 49. 1 ms … 39 Tburst = 15 bit = 1. 56 ms or Sync PPDU I 0 Sync PPDU Q Tw Sync 41 40 Sync PPDU I 0 … PPDU Q 39 Tw Tw=3. 3 ms T=T 0 Sync 41 40 39 … Sync 0 T 0 > Tburst+Tp+T 2=53. 8 ms Tw T = T 0+k*Tframe Tw Tw T 2= 2*Tburst = 3. 1 ms Tw A sensing device has the flexibility to choose any value in {0, 1, 2 …} as k T T 1 > T 0 -Tw+2*Tburst =T 0 -0. 2 Submission ensure one of short window capture Sync 13 62. 6 ms > T 0 > 53. 8 ms Zander LEI, I 2 R Singapore

December 2007 doc. : IEEE 802. 22 -07/0570 r 0 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 Submission 14 Zander LEI, I 2 R Singapore

December 2007 doc. : IEEE 802. 22 -07/0570 r 0 Summary • Enhancement to Beacon Transmission – – Submission 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 15 Zander LEI, I 2 R Singapore