1. New Beacon Exchange Scheme for the 802.22.1
Nov 2006
doc.: IEEE /0xxxr1
January 2007
New Beacon Exchange Scheme for the
IEEE P Wireless RANs Date:
Author(s):
Name
Company
Address
Phone
Linjun Lv
Huawei Technologies
Shenzhen, China
Zhou Wu
Mingwei Jie
Kexue Wang
Soo-Young Chang
Davis, CA, U.S.
Jianwei Zhang
Shanghai, China
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 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 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at
>
Linjun Lv, Huawei Technologies
Wu Yu-Chun, Huawei Hisi

2. Nov 2006
doc.: IEEE /0xxxr1
January 2007
Abstract
In this contribution, a scheme is proposed to enhance the performance when multiple SPDs attempt to send RTS at the same time.
This scheme proposed in this contribution provides more flexibility to process the collision situations and more efficient to decrease the probabilities of collision.
Linjun Lv, Huawei Technologies
Wu Yu-Chun, Huawei Hisi

3. BACKGROUND FROM P802.22.1/PRE-D1
Nov 2006
doc.: IEEE /0xxxr1
January 2007
BACKGROUND FROM P /PRE-D1
Data Transfer Model:
From primary to secondary protecting device
(from PPD to SPD)
From secondary to primary protecting device
(from SPD to PPD)
Linjun Lv, Huawei Technologies
Wu Yu-Chun, Huawei Hisi

4. FROM PPD TO SPD Steps: PPD places the information in its beacon PSDU.
Nov 2006
doc.: IEEE /0xxxr1
January 2007
FROM PPD TO SPD
Steps:
PPD places the information in its beacon PSDU.
SPD monitors the beacon PSDU.
SPD decodes its address and recovers the message.
No acknowledgement of data reception is provided.
Primary Protecting Device
(PPD)
Secondary Protecting Device
(SPD)
Beacon with information attached
Linjun Lv, Huawei Technologies
Wu Yu-Chun, Huawei Hisi

5. Nov 2006
doc.: IEEE /0xxxr1
January 2007
FROM SPD TO PPD
Primary Protecting Device
Secondary Protecting Device
Beacon
Interrupt burst
ACK sent during ANP
Steps:
SPD sends an RTS burst to the PPD during the receive period.
PPD responds an ACK or a NACK in the ANP.
PPD yields the beacon portion of the following superframe to the SPD.
SPD transmits its own beacon, containing its data during this time.
PPD continues the superframe by monitoring the channel during the receive period.
Linjun Lv, Huawei Technologies
Wu Yu-Chun, Huawei Hisi

6. 1ST DATA EXCHANGE, FROM SPD TO PPD
Nov 2006
doc.: IEEE /0xxxr1
January 2007
1ST DATA EXCHANGE, FROM SPD TO PPD …
Sync N
Beacon Rx
period
SPD
RTS burst
received by PPD
PPD
transmits
ANP
(ACK)
Steps:
PPD transmits the synchronization bursts and the beacon frame.
PPD enables its receiver to listen for an RTS burst from a SPD.
PPD receives an RTS burst.
PPD transmits an ACK.
Linjun Lv, Huawei Technologies
Wu Yu-Chun, Huawei Hisi

7. 2ND DATA EXCHANGE, FROM SPD TO PPD
Nov 2006
doc.: IEEE /0xxxr1
January 2007
2ND DATA EXCHANGE, FROM SPD TO PPD …
Sync N
Beacon Rx
period
ANP
(NACK) no
RTS burst
received by PPD
SPD
transmits
PPD
Steps:
PPD transmits the synchronization bursts.
SPD transmits the beacon frame.
PPD enables its receiver to listen for an RTS burst from an SPD.
If the PPD does not receive an RTS burst, the PPD transmits a NACK.
Linjun Lv, Huawei Technologies
Wu Yu-Chun, Huawei Hisi

8. 3RD DATA EXCHANGE, FROM SPD TO PPD
Nov 2006
doc.: IEEE /0xxxr1
January 2007
3RD DATA EXCHANGE, FROM SPD TO PPD …
Sync N
Beacon Rx
period
ANP
(NACK)
PPD
transmits no
RTS burst
received by PPD
Steps:
PPD transmits the synchronization bursts and the beacon frame.
PPD then enables its receiver to listen for an RTS burst from an SPD.
If the PPD does not receive an RTS burst, the PPD transmits a NACK.
Linjun Lv, Huawei Technologies
Wu Yu-Chun, Huawei Hisi

9. DISADVANTAGES If multiple SPDs send RTS in the Rx period,
Nov 2006
doc.: IEEE /0xxxr1
January 2007
DISADVANTAGES
If multiple SPDs send RTS in the Rx period,
It entails a collision.
PPD issues a NACK and does not allow any SPDs to send beacon in the next superframe.
The next superframe always can not be used to send a beacon frame by SPDs.
If an SPD can not send all the protecting information to PPD in one superframe,
The SPD has to send an RTS to request to send in the next superframe.
The SPD may need to compete with other SPDs for the next superframe.
The SPD may not send the remnant information in a period of time, which will go against the message integrity.
Linjun Lv, Huawei Technologies
Wu Yu-Chun, Huawei Hisi

10. New Additional Feedback:
January 2007
PROPOSED SOLUTION
Existing Feedback:
Transmission
Bits: 0 1 2 3
ACK
NACK
New Additional Feedback:
Transmission
Bits: 0 1 2 3
GO-ON
By introducing the GO-ON feedback, the PPD can be more flexible to select a SPD which can send a beacon in the next superframe.
Linjun Lv, Huawei Technologies

11. NEW BEACON STATUS INDICATION
January 2007
NEW BEACON STATUS INDICATION
Beacon frame format (MPDU)
Bits:0-5 6 7
Reserved
NST
Keep out zone
Revised format of the parameter 2 field
Linjun Lv, Huawei Technologies

12. NST Next Superframe to Continue Transmitting Beacon Indication
Nov 2006
doc.: IEEE /0xxxr1
January 2007
NST
Next Superframe to Continue Transmitting Beacon Indication
Both PPD and SPD can set its value.
Indicating whether the next superframe can be used to transmit beacons or not.
Combining with device rank (PPD or SPD) field in Parameter 1, other protecting devices can take next actions.
Linjun Lv, Huawei Technologies
Wu Yu-Chun, Huawei Hisi

13. PPD AND SPD BEHAVIOR FOR DIFFERENT NST & DEVICE RANK
Nov 2006
doc.: IEEE /0xxxr1
January 2007
PPD AND SPD BEHAVIOR FOR DIFFERENT NST & DEVICE RANK
Device Rank
NST
Beacon State 1
A beacon is transmitted by the PPD and the next superframe can be reserved for other protecting devices to send beacons.
A beacon is transmitted by the PPD and in the next superframe the PPD will continue issuing a beacon.
A beacon is transmitted by the SPD, but in the next superframe the SPD shall not continue issuing a beacon or compete with other SPDs to issue a beacon.
A beacon is transmitted by the SPD, and in the next superframe the SPD shall continue issuing a beacon to the PPD.
Linjun Lv, Huawei Technologies
Wu Yu-Chun, Huawei Hisi

14. PPD CONTINUES ISSUING BEACONS
Nov 2006
doc.: IEEE /0xxxr1
January 2007
PPD CONTINUES ISSUING BEACONS
PPD’s task:
Acts as a protecting device.
Combines all other SPDs’ beacon information.
Controls other SPDs’ beacon transmission.
PPD has plentiful information to sent.
PPD sets device rank to 1 and NST to 1.
Other SPDs shall not issue RTS in the Rx period.
PPD sends the remnant information in the following frames.
Linjun Lv, Huawei Technologies
Wu Yu-Chun, Huawei Hisi

15. SPD REQUESTS TO ISSUE A BEACON
Nov 2006
doc.: IEEE /0xxxr1
January 2007
SPD REQUESTS TO ISSUE A BEACON
PPD has no or little information to send:
PPD sets device rank to 1 and NST to 0.
SPDs issue RTS to compete for the next superframe.
PPD issues an ACK or a NACK. 
If only one SPD issues an RTS, the PPD will issue an ACK.
If more than one SPD issue RTS and so a collision occurs, the PPD will issue a NACK.
Linjun Lv, Huawei Technologies
Wu Yu-Chun, Huawei Hisi

16. SPD STOPS ISSUING BEACONS
Nov 2006
doc.: IEEE /0xxxr1
January 2007
SPD STOPS ISSUING BEACONS
SPD has sent all its information in one superframe:
This SPD sets device rank to 0 and NST to 0.
SPDs issue an RTS to compete for the next superframe.
PPD issues an ACK or a NACK. 
If only one SPD issues an RTS, the PPD will issue an ACK.
If more than one SPD issue RTS and so a collision occurs, the PPD will issue a NACK.
Linjun Lv, Huawei Technologies
Wu Yu-Chun, Huawei Hisi

17. SPD CONTINUES ISSUING BEACONS
Nov 2006
doc.: IEEE /0xxxr1
January 2007
SPD CONTINUES ISSUING BEACONS
SPD has plentiful information to send:
If other SPDs do not issue RTS in the Rx period:
The SPD sets device rank to 0 and NST to 1.
Other SPDs do not issue RTS in the Rx period.
The PPD will issue a GO-ON and assign the next superframe to the SPD to send its continuous beacons.
2. If other SPDs force to issue RTS in the Rx period:
If multiple SPDs compete with this SPD, the PPD may issue a NACK to reject all the SPDs (including the former SPD) or a GO-ON to allow the former SPD to continue sending;
If only one SPD competes with this SPD, the PPD may issue an ACK to allow the competing SPD to send or a GO-ON to allow the former SPD to continue sending.
Linjun Lv, Huawei Technologies
Wu Yu-Chun, Huawei Hisi

18. COMPARING WITH RANDOM BACKOFF ALGORITHM IN CASE OF COLLISIONS
Nov 2006
doc.: IEEE /0xxxr1
January 2007
COMPARING WITH RANDOM BACKOFF ALGORITHM IN CASE OF COLLISIONS
By setting NST to 1, the former SPD can continue to use the next superframe without sending an RTS.
(2) By setting NST to 1, other SPDs may not issues RTS to compete for the next superframe, which decrease the probability of collision.
(3) Even if contesting SPD issues beacon in current superframe to compete with the former SPD, PPD can broadcast ACK or NACK or GO-ON in the ANP to select one to transmit.
Linjun Lv, Huawei Technologies
Wu Yu-Chun, Huawei Hisi

19. January 2007
SIMULATION RESULTS
Plot throughput of beacons vs various probabilities of collision
the throughput of beacons is the average bytes of the beacons in one superframe.
Linjun Lv, Huawei Technologies

20. January 2007
SIMULATION RESULTS
Linjun Lv, Huawei Technologies

21. Nov 2006
doc.: IEEE /0xxxr1
January 2007
CONCLUSIONS
If the PPD requests to issue its continuous beacon in the next superframe, other SPDs shall not contest with it.
If the SPD requests to issue its continuous beacon in the next superframe, other SPDs may not compete with it and the SPD can ensure its message integrity.
If the SPD requests to issue its continuous beacon in the next superframe, other SPDs may compete with it, but only the PPD decides which SPD to transmit in the next superframe through issuing an ACK、a NACK or a GO-ON.
The simulations results show that the scheme proposed here has better performance than the current scheme.
Linjun Lv, Huawei Technologies
Wu Yu-Chun, Huawei Hisi

22. Nov 2006
doc.: IEEE /0xxxr1
January 2007
Reference
[1] Motorola “Part 22.1: Enhanced Protection for Low Power Licensed devices Operating in TV Broadcast Bands”...
Linjun Lv, Huawei Technologies
Wu Yu-Chun, Huawei Hisi

23. Any comments and questions will be highly appreciated!
Nov 2006
doc.: IEEE /0xxxr1
January 2007
Thank you!
Any comments and questions
will be highly appreciated!
Linjun Lv, Huawei Technologies
Wu Yu-Chun, Huawei Hisi