1. doc.: IEEE 802.22-07/0008r0 Submission January 2007 Slide 1Linjun Lv, Huawei Technologies Backup Primary Protecting Devices for Beacon Devices IEEE P802.22 Wireless RANs Date: 2007-1-5 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 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 802.22 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at patcom@iee.org.patcom@iee.org >

2. doc.: IEEE 802.22-07/0008r0 Submission January 2007 Slide 2Linjun Lv, Huawei Technologies Abstract This proposal introduces a backup primary protecting device which can be a PPD immediately if the current PPD fails its work to offer enhanced protection for low-power, licensed devices operating in television broadcast bands. Simulation results are suggested which show performance improvement.

3. doc.: IEEE 802.22-07/0008r0 Submission January 2007 Slide 3Linjun Lv, Huawei Technologies If a PPD Stops Transmitting Abruptly… If a SPD misses aMaxMissedBeacons for consecutive beacon frames, the SPD will negotiate and find a SPD as a new PPD. The new PPD will enter the initial transmission period, for a period of 30 seconds. But this negotiation and initial transmission period is a long time and can not protect Part 74 device in a timely manner.

4. doc.: IEEE 802.22-07/0008r0 Submission January 2007 Slide 4Linjun Lv, Huawei Technologies Proposed Solution A backup primary protecting device (BPPD) –When a PPD is working: The PPD will choose one or several SPDs as BPPDs, and assign different priorities for every BPPD; –When a PPD doesn’t work : The BPPD with the highest priority (main BPPD) will promote itself to a new PPD immediately; BPPDs with other priorities (subordinative BPPDs) will increase respective priorities, and the BPPD with the highest priority will promote itself to a new main BPPD immediately.

5. doc.: IEEE 802.22-07/0008r0 Submission January 2007 Slide 5Linjun Lv, Huawei Technologies How to Choose BPPD? The support of the next higher layer (NHL): –Add a primitive of MLME-BPPD MLME-BPPD. Request NHL to MLME MLME-BPPD. indication MLME to NHL MLME-BPPD. Confirm NHL to MLME

6. doc.: IEEE 802.22-07/0008r0 Submission January 2007 Slide 6Linjun Lv, Huawei Technologies How to Choose BPPD? (1) MLME-BPPD.request parameters Name TypeValid rangeDescription StatusInteger0-1 0 ： choose BPPD based on method 0, that is choose the first SPD that transmit beacon after received indication 1 ： reserved MLME-BPPD. indication parameters Name TypeValid rangeDescription SPD Addressthe address of SPD MLME-BPPD.confirm parameters Name TypeValid rangeDescription StatusInteger0-1 1 ： choose the received SPD as BPPD 0 ： don’t choose the received SPD as BPPD

7. doc.: IEEE 802.22-07/0008r0 Submission January 2007 Slide 7Linjun Lv, Huawei Technologies How to Choose BPPD? (2) When the PPD received the first beacon frame of the SPD after indication from the next higher layer, the PPD can choose this SPD as a BPPD and memorize its Source Address. –Add a BPPD Address in beacon frame to notify BPPD’s identity to the SPD. BPPD Address is zero before the PPD choose a BPPD; –Add a BPPD Priority in beacon frame to notify BPPD’s Priority.

8. doc.: IEEE 802.22-07/0008r0 Submission January 2007 Slide 8Linjun Lv, Huawei Technologies How to Choose BPPD? (3) Octets: 168 Frame Payload Parameter 3 Parameter 2 TimestampLocation Source Address Parameter 1 n611 MHR MAC payload Message Integrity Code 16 MFR Sub channel Map 5 BPPD Priority 1 BPPD Address 6 New Beacon frame format BPPD PriorityDescription 0000Don’t choose BPPD 0001The first priority 0010The second priority 0011The third priority ……etc BPPD Priority format

9. doc.: IEEE 802.22-07/0008r0 Submission January 2007 Slide 9Linjun Lv, Huawei Technologies How to Work? For three cases PPD is working, but BPPD dies PPD dies, but BPPD is working Both PPD and BPPD die

10. doc.: IEEE 802.22-07/0008r0 Submission January 2007 Slide 10Linjun Lv, Huawei Technologies PPD Is Working, but BPPD Dies… (1) BPPD ANP was inserted between Rx period and ANP. Its length is 2bits. Main BPPD can notify whether it is active or not in this BPPD ANP period. ANPBPPD ANP … SyncN 0BeaconRx period New Superframe format BPPD ANP Description 00BPPD will cease transmission in the next superframe 11BPPD is active 01, 10 reserved

11. doc.: IEEE 802.22-07/0008r0 Submission January 2007 Slide 11Linjun Lv, Huawei Technologies PPD Is Working, but BPPD Dies… (2) If PPD and subordinative BPPDs received 00 in the BPPD ANP period: –Main BPPD will cease transmission in the next superframe; –If there is subordinate BPPD: The subordinative BPPD will increase respective priorities. The BPPD with the highest priority in subordinative BPPD will promote itself to new main BPPD immediately, and transmit BPPD burst in the next frame. –If there is no subordinative BPPD: the PPD needs to re-choose a BPPD. If PPD and subordinative BPPD miss aMaxMissedBPPD in a consecutive BPPD burst: –PPD and subordinative BPPD will consider that main BPPD does not work; –The same process as above situation; –The default value of aMaxMissedBPPD is 2.

12. doc.: IEEE 802.22-07/0008r0 Submission January 2007 Slide 12Linjun Lv, Huawei Technologies PPD Dies, but BPPD Is Working… Case 1: If PPD notify BPPD and SPD that it is planning to cease transmission by Cease Tx, main BPPD will promote itself to a new PPD in the next superframe. The BPPD with the highest priority in subordinative BPPD will promote itself to new main BPPD. Case 2: If PPD do not set Cease Tx to one and BPPD misses aMaxMissedPPD in consecutive beacon frame, main BPPD will consider that this PPD does not work and promote itself to new PPD: –The default value of the period of superframe is 8*(383*3+55)/9609 = 1.002394 s –So the default value of aMaxMissedPPD can be one. –The BPPD with the highest priority in subordinative BPPDs will promote itself to new main BPPD.

13. doc.: IEEE 802.22-07/0008r0 Submission January 2007 Slide 13Linjun Lv, Huawei Technologies Both PPD and BPPD Die… This situation may be occurred when: –PPD dies, and in the next aMaxMissedPPD consecutive superframe main BPPD also dies; –Main BPPD dies, and in the next aMaxMissedBPPD consecutive superframe PPD also dies; The above situation can be summarized : –If SPD misses aMaxMissedBeacons in a consecutive beacon frame, SPD will consider that both PPD and main BPPD do not work if there is subordinative BPPD, the BPPD with the highest priority in subordinative BPPD will promote itself to new PPD immediately; if there is no subordinative BPPD, SPD will negotiation and find a new PPD, after that perform initial transmission period. aMaxMissedBeacons can be set as MAX(aMaxMissedPPD ， aMaxMissedBPPD) ＋ 1.

14. doc.: IEEE 802.22-07/0008r0 Submission January 2007 Slide 14Linjun Lv, Huawei Technologies Simulations In this simulation, relationships –between the average reinitialization time and probability of stop working, –between the average reinitialization time and the number of BPPDs, –between the average reinitialization time and aMaxMissedBPPD, and –between the average reinitialization time and aMaxMissedPPD are shown.

15. doc.: IEEE 802.22-07/0008r0 Submission January 2007 Slide 15Linjun Lv, Huawei Technologies Simulation Results (1) Average reinitialization time (second) vs probability that protect device stops working

16. doc.: IEEE 802.22-07/0008r0 Submission January 2007 Slide 16Linjun Lv, Huawei Technologies Simulation Results (2) Average reinitialization time (second) vs number of BPPDs

17. doc.: IEEE 802.22-07/0008r0 Submission January 2007 Slide 17Linjun Lv, Huawei Technologies Simulation Results (3) Average reinitialization time (second) vs aMaxMissedBPPD

18. doc.: IEEE 802.22-07/0008r0 Submission January 2007 Slide 18Linjun Lv, Huawei Technologies Simulation Results (4) Average reinitialization time (second) vs aMaxMissedPPD

19. doc.: IEEE 802.22-07/0008r0 Submission January 2007 Slide 19Linjun Lv, Huawei Technologies Conclusion With the scheme proposed in this contribution, we can basically avoid negotiation and initial transmission period of 30 seconds and ensure protection of Part 74 device.

20. doc.: IEEE 802.22-07/0008r0 Submission January 2007 Slide 20Linjun Lv, Huawei Technologies References [1] Motorola “Part 22.1: Enhanced Protection for Low Power Licensed devices Operating in TV Broadcast Bands”.