1. Common Quiet Times for Spectrum Sensing
November 2007
doc.: IEEE yy/xxxxr0
November 2007
Common Quiet Times for Spectrum Sensing
IEEE P Wireless RANs Date:
Authors:
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Steve Shellhammer, Qualcomm
Steve Shellhammer, Qualcomm

2. November 2007
Abstract
Quiet times are used to sense for a variety of signal types. It would be useful if a common quiet time can be used to sense for multiple signal types. By using a comment quiet time the overall sensing time can be minimized.
This presentation argues for agreeing on a recommended common quiet time
An implementation would not be required to use this recommended common quiet time
Steve Shellhammer, Qualcomm

3. Question for this Discussion
November 2007
Question for this Discussion
Can most (or all) of the sensing technique use a common quiet time?
We allow each sensing technique to use multiple quiet times
If multiple quiet times are used we would need to allow some time between these quiet times, to allow WRAN traffic flow
Steve Shellhammer, Qualcomm

4. Multiple Sensing Times
November 2007
Multiple Sensing Times
Quiet time
Quiet time
Quiet time
If a long sensing time is needed it is very beneficial to divide the quiet time into a sequence of smaller quiet times
Latency impact is TS versus N TS
Steve Shellhammer, Qualcomm

5. November 2007
What works for Beacon
The sync burst requires a quiet time of 5.1 ms
A much longer time is used infrequently to detect the entire frame
A common quiet time should be at least 5.1 ms
Steve Shellhammer, Qualcomm

6. Sensing for ATSC and Wireless Microphones
November 2007
Sensing for ATSC and Wireless Microphones
Some techniques can potentially divide the full sensing time into a sequence of separate quiet times
Energy detection
Pilot-based techniques
Some techniques may not be able to divide the sensing time into a sequence of sensing times
PN sequence-based techniques
For each sensing technique we would need to know that smallest TS that would be practical
Steve Shellhammer, Qualcomm

7. November 2007
Possible Actions
For each sensing technique evaluate the smallest TS that can be used
Summarize the results from each of these evaluations
Agree on a value for TS
Rerun simulations using multiple disjoint quiet times of duration TS
Report on the number of quiet times required for each sensing technique
Should the WG pursue this approach?
Steve Shellhammer, Qualcomm