1 Sensing Techniques - IEEE 802 LAN/MAN Standards Committee

May 2007
IEEE 802.22-07/0261r1
IEEE P802.22
Wireless RANs
Outline of Informative Annex on Sensing Techniques
Date: 2007-05-31
Steve Shellhammer
5775 Morehouse Drive
San Diego, CA 92121
(858) 658-1874
[email protected]
This document contains an outline of the Informative Annex on sensing techniques.
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 <[email protected]>.
page 1
Steve Shellhammer, Qualcomm
May 2007
IEEE 802.22-07/0261r1
1 Sensing Techniques
This annex contains descriptions of a number of sensing techniques. A sensing technique is an implementation of
the spectrum sensing function.
There are several classifications of sensing techniques. First a sensing technique can be classified as either signal
specific or blind. A signal specific sensing technique is based on features of specific signal type. A blind sensing
technique does not rely on features of a specific signal type.
A sensing technique can be classified as either a fine sensing technique or a coarse sensing technique. A fine
sensing technique is able to detect the presence of a signal at the required signal power level. A coarse sensing
technique may not be able to detect the presence of a signal at the required signal power; however, it may still be
useful for detecting higher-power signals often is a shorter period of time.
Each sub-clause in this annex describes a specific sensing technique. The first three sensing techniques are blind
sensing techniques and the next seven are signal specific sensing techniques.
Performance for each of the sensing techniques is also included in each sub-clause. The primary performance
metric is the required SNR at which the probability of detection is greater or equal to 0.9 for all multipath
conditions. For the ATSC signals the multipath was modelled by using twelve representative signals from [1].
For each sensing technique the sensing time is also included. In many cases if the sensing time is increased the
required SNR will decrease.
Some sensing techniques are sensitive to uncertainty in the noise power. In other words the estimate of the noise
power PˆN is with Δ of the true noise power,
PˆN  PN  PE
  PE  
In some sensing techniques the detector threshold is a function of the noise power estimate, so an error in that
estimate can affect the detector performance.
If the sensing technique is sensitive to noise uncertainty then the required SNR is give for various values of the
noise uncertainty parameter Δ.
1.1 Blind Sensing Techniques
A blind sensing technique does not depend on specific signal features. There are three blind sensing techniques
described in this annex: the energy detector, the eigenvalue sensing technique and the multi-resolution sensing
Energy (Power) Detector
page 2
Steve Shellhammer, Qualcomm
May 2007
IEEE 802.22-07/0261r1
Eigenvalue Sensing Technique
Multi-resolution Sensing Technique
1.2 Signal Specific Sensing Techniques
A signal specific sensing technique relies upon specific signal features. There are seven signal specific sensing
techniques described in this annex. Six of the techniques are for ATSC signals and one of the techniques is for
wireless microphones.
ATSC Signature Sequence Correlation Sensing Technique
ATSC FFT-based Pilot Sensing Technique
ATSC PLL-based Pilot Sensing Technique
Wireless Microphone Covariance Sensing Technique
page 3
Steve Shellhammer, Qualcomm
May 2007
IEEE 802.22-07/0261r1
ATSC Pilot Covariance Sensing Technique
ATSC Spectral Correlation Sensing Technique
ATSC Cyclostationary Sensing Technique
Advanced Television Standards Committee, ATSC Recommended Practice: Receiver
Performance Guidelines, ATSC A74, June 2004
page 4
Steve Shellhammer, Qualcomm