1. An Enhanced Quiet Period Synchronization Method for 802.22 Networks
Month Year
doc.: IEEE yy/xxxxr0
Nov/2008
An Enhanced Quiet Period Synchronization Method for Networks
IEEE P Wireless RANs Date:
Authors:
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Haiguang Wang, Hisilicon Technologies
John Doe, Some Company

2. Month Year
doc.: IEEE yy/xxxxr0
Nov/2008
Abstract
According to our study, we found that the current design of standard in quiet period synchronization is incomplete. The mainly problem is the synchronized quiet period cannot be reduced when it could be. This may cause resource wastage. In this proposal, we propose a method that solves the above problem and the synchronized quiet period can be either increased or reduced.
This contribution is a proposed resolution for comment for and
Haiguang Wang, Hisilicon Technologies
John Doe, Some Company

3. Two Types of Quiet Period How to specify the quiet period
Nov/2008
Quiet Period
In IEEE Networks, Quiet Period (QPs) are scheduled for Spectrum Sensing and two types of QPs are defined:
QP for Intra-frame Sensing, specified by
Cycle length
Offset
Bitmap
Duration
QP for Inter-frame Sensing
Time To Quiet Period (TTQP)
Duration of Quiet Period (DQP)
Two Types of Quiet Period
How to specify the quiet period
Haiguang Wang, Hisilicon Technologies

4. Quiet Period Synchronization
Month Year
doc.: IEEE yy/xxxxr0
Nov/2008
Quiet Period Synchronization
Quiet Period (QP) Synchronization is important for network。
According to the standard, overlapping are required to synchronize their QP.
Quiet period after synchronization
Haiguang Wang, Hisilicon Technologies
John Doe, Some Company

5. Problem with Intra-frame Sensing Synchronization
Nov/2008
Problem with Intra-frame Sensing Synchronization
With the parameters specified by current design, it is hard for the BSs to synchronize to a smaller QP duration than the current one. However, this may happen when the required QP duration of certain BS changes.
Variables to describe the QP synchronization
: minimal requirement on QP duration of BSi.
: the currently synchronized QP duration of BSi. ? 1 2 1 2 1 2
A. Before synchronization
B. After synchronization
C. Required QP changed, how to process this scenario?
Haiguang Wang, Hisilicon Technologies

6. Our Solution: Using Synchronization Counter (SC)
Nov/2008
Our Solution: Using Synchronization Counter (SC)
Each BS maintains a synchronization counter, named as , for QPD of Intra-frame Sensing.
takes value from 1 to SCmax.
SCmax is a predefined value.
The value of is transmitted together with the value of , which is corresponding to the field of Intra-frame Sensing Duration in SCH or CBP messages.
Haiguang Wang, Hisilicon Technologies

7. Algorithm to Update the Synchronization Counter
Nov/2008
Algorithm to Update the Synchronization Counter
Haiguang Wang, Hisilicon Technologies

8. Simulation Configuration
Nov/2008
Simulation Configuration
Simulator: NS2
Configuration Parameters
Region: 100km x 100km
Number of BSs: 20
Tx power of BS: 4 Watts.
Antenna gain: 6dB.
Path loss model: polynomial power decay with the expontent of 2.6.
Radio transmission range: 33 kilometers.
Channel bandwidth: 6MHz
Modulation: QPSK with 1/2coding.
Transmission rate: 4.5Mbps.
We choose SCmax : 15.
The location of BSs in the region
Haiguang Wang, Hisilicon Technologies

9. Simulation Results The mean time for synchronization.
Nov/2008
Simulation Results
The mean time for synchronization.
Synchronize to a longer duration: 0.93 seconds.
Synchronize to a shorter duration: 1.21 seconds.
The variation of Synchronized Quiet Period
The detailed synchronization process
Haiguang Wang, Hisilicon Technologies

10. Nov/2008
Proposed Text 1/3
Insert text in table 1 after the entry for “Intra-frame Sensing Duration” as follows:
Intra-frame Sensing Duration
5 bits
Valid only if Intra-frame Sensing Cycle Length > 0.
If this field is set to a value different from 0 (zero): It indicates the number of symbols starting from the end of the frame that shall be used to perform intra-frame sensing.
Synchronization Counter for Intra-frame Sensing Duration
8 bits
Valid only if Intra-frame Sensing Duration > 0.
This field is used for the purpose of Intra-frame Sensing Duration synchronization among overlapping BSs.
Haiguang Wang, Hisilicon Technologies

11. Figure xxx: Algorithm to update the Intra-frame Sensing Duration
Nov/2008
Proposed Text 2/3
Insert text and figure in after the third paragraph as follows:
In order to allow the Intra-frame Sensing Duration after synchronization adapt to the variation of Intra-frame Sensing Duration, each BS, denoted as BSi, should maintain a variable named Synchronization Counter for Intra-frame Sensing Duration, denoted as This value is sent together with Intra-frame Sensing Duration in SCH and CBP. It should be updated according to following algorithms:
Figure xxx: Algorithm to update the Intra-frame Sensing Duration
Haiguang Wang, Hisilicon Technologies

12. Proposed Text 3/3 And followed by text after the proposed figure:
Nov/2008
Proposed Text 3/3
And followed by text after the proposed figure:
where
is the currently synchronized Intra-frame Sensing Duration of BSi and
is the minimum requirement on Intra-frame Sensing Duration by BSi. SCmax is predefined value.
Haiguang Wang, Hisilicon Technologies

13. Nov/2008
Conclusion
We need add in one more field for synchronization counter in SCH or CBP messages. The length of field is 8 bits.
Similar, the method can apply to the synchronization of following fields for Intra-frame sensing:
Intra-frame sensing cycle length
Intra-frame sensing bitmap
Haiguang Wang, Hisilicon Technologies

14. Nov/2008
References
IEEE P DRAFTv1.1 Draft Standard for Wireless Regional Area Networks Part 22: Cognitive Wireless RAN Medium Access Control (MAC) and Physical Layer (PHY) speci¯cations: Policies and procedures for operation in the TV BandsMarch 2008.
wran-draft-1-0-draft-comments-database
Haiguang Wang, Hisilicon Technologies