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Doc.: IEEE 802.22-07/0052r0 Submission January 2007 Steve Shellhammer, QualcommSlide 1 The Spectrum Sensing Function IEEE P802.22 Wireless RANs Date: 2007-01-15.

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Presentation on theme: "Doc.: IEEE 802.22-07/0052r0 Submission January 2007 Steve Shellhammer, QualcommSlide 1 The Spectrum Sensing Function IEEE P802.22 Wireless RANs Date: 2007-01-15."— Presentation transcript:

1 doc.: IEEE /0052r0 Submission January 2007 Steve Shellhammer, QualcommSlide 1 The Spectrum Sensing Function IEEE P Wireless RANs Date: Authors: 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 IEEEs name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEEs 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 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 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at >

2 doc.: IEEE /0052r0 Submission January 2007 Steve Shellhammer, QualcommSlide 2 Abstract This presentation is to describe the Spectrum Sensing Black Box It defines the inputs and outputs of the spectrum sensing function without specifying the specific techniques used within the black box.

3 doc.: IEEE /0052r0 Submission January 2007 Steve Shellhammer, QualcommSlide 3 Acronyms ACLAvailable Channel List ACSFAvailable Channel Selection Function CMConfidence Metric CVConfidence Vector EVError Variance EVVError Variance Vector FSEField Strength Estimate FSEVField Strength Estimate Vector

4 doc.: IEEE /0052r0 Submission January 2007 Steve Shellhammer, QualcommSlide 4 Acronyms SPDSignal Present Decision SPVSignal Present Vector SSFSpectrum Sensing Function SWSSensing Window Specification SWSVSensing Window Specification Vector

5 doc.: IEEE /0052r0 Submission January 2007 Steve Shellhammer, QualcommSlide 5 Definitions Available Channel List A list of which TV channels are available for use by the WRAN. The list is sorted in order of preference. The first channel in the list is the most preferred channel for use by the WRAN. The last channel in the list is the least preferred channel. Any channel not on the list shall not be used by the WRAN. Available Channel Selection Function The function that combines the outputs of the spectrum scanning function from the base station and the CPEs and produces the available channel list Confidence MetricA metric indicating the confidence in a signal present decision Confidence VectorA vector of confidence metrics

6 doc.: IEEE /0052r0 Submission January 2007 Steve Shellhammer, QualcommSlide 6 Definitions Error VarianceThe variance of the error of a field strength estimate Error Variance Vector A vector of error variances Field Strength Estimate An estimate of the field strength of a specific signal at the WRAN station Field Strength Estimate Vector A vector of field strength estimates Sensing ModeA mode that specifies the output of the spectrum sensing function Signal Type VectorA vector of bits. If a bit is set to a 1 then that signal type is to be sensed. If a bit is set to a 0 then that signal type is not to be sensed.

7 doc.: IEEE /0052r0 Submission January 2007 Steve Shellhammer, QualcommSlide 7 Definitions Spectrum Scanning Function The function of scanning a TV channel for a set of signal types and generating a set of metrics indicating the presence of each of the signal types in the specified TV channel Sensing Window Specification A specification of the number of sensing intervals and the duration of the intervals Sensing Window Specification Vector A vector of sensing window specifications

8 doc.: IEEE /0052r0 Submission January 2007 Steve Shellhammer, QualcommSlide 8 Requirement for the SSF The spectrum sensing function (SSF) shall be present in the base station and each CPE

9 doc.: IEEE /0052r0 Submission January 2007 Steve Shellhammer, QualcommSlide 9 SSF Inputs Channel NumberThe TV channel number specifying which channel to sense. Signal Type VectorA vector of bits. The i-th entry in the vector corresponds to the i-th signal type specified in Table 70 in the working document. A 1 in the i-th element in the vector indicates the SSF should sense for the i-th signal type. A 0 in the i-th element of the vector indicates that the SSF should not sense for the i-th signal type Sensing Window Specification Vector A vector of sensing window specifications Sensing ModeThe mode specifies the output of the SSF. There are three modes. Maximum probability of false alarm The maximum probability of false alarm for the SSF when operating in Mode 1 or Mode 2

10 doc.: IEEE /0052r0 Submission January 2007 Steve Shellhammer, QualcommSlide 10 SSF Modes Three modes of the SSF have been defined The output of the SSF is different depending on the sensing mode

11 doc.: IEEE /0052r0 Submission January 2007 Steve Shellhammer, QualcommSlide 11 Sensing Window Specification A sensing window consists of N sensing intervals –If a continuous window is required N is set to 1 Each sensing interval is of duration T 1 The spacing between sensing (T 2 ) intervals is not necessarily a fixed time. It is specified to between a minimum and maximum value

12 doc.: IEEE /0052r0 Submission January 2007 Steve Shellhammer, QualcommSlide 12 Sensing Window Specification

13 doc.: IEEE /0052r0 Submission January 2007 Steve Shellhammer, QualcommSlide 13 Summary of Sensing Modes Mode 0 –Signal present vector: A vector indicating the whether specific signal types are present in the channel Mode 1 –Signal present vector –Confidence vector – A vector of confidence metrics Mode 2 –Field strength estimate vector: A vector of field strength estimates –Error variance vector: A vector consisting of the variance of the estimation errors

14 doc.: IEEE /0052r0 Submission January 2007 Steve Shellhammer, QualcommSlide 14 SSF in Mode 0

15 doc.: IEEE /0052r0 Submission January 2007 Steve Shellhammer, QualcommSlide 15 Specifications on SSF Outputs in Mode 0 The SSF shall sense channel specified by the channel number with a sensing window according to the sensing window specification for each signal type being sensed When the i-th signal type is not present in the channel then the probability that the signal present decision is TRUE shall be less than the specified Maximum probability of false alarm When the i-th signal type is present in the channel at the signal power level defined in Table TBD then the probability that the signal present decision is TRUE shall be greater than 0.9

16 doc.: IEEE /0052r0 Submission January 2007 Steve Shellhammer, QualcommSlide 16 SSF in Mode 1

17 doc.: IEEE /0052r0 Submission January 2007 Steve Shellhammer, QualcommSlide 17 Specifications on SSF Outputs in Mode 1 In addition to the specification for the SSF in Mode 0 we have the following specifications For each signal type being sensed according to the signal type vector we have, –The confidence metric will be a number greater than 0 and less than CM MAX (TBD) –When SPD = TRUE the CM increases with increasing SNR –When SPD = FALSE the CM increases with decreasing SNR

18 doc.: IEEE /0052r0 Submission January 2007 Steve Shellhammer, QualcommSlide 18 SSF in Mode 2

19 doc.: IEEE /0052r0 Submission January 2007 Steve Shellhammer, QualcommSlide 19 Specifications on SSF Outputs in Mode 2 The field strength estimate shall be an unbiased estimator The range of the field strength estimate shall be between FS MIN (TBD) and FS MAX (TBD) The average error variance shall decrease with increasing SNR The range of the error variance shall be between EV MIN (TBD) and EV MAX (TBD)

20 doc.: IEEE /0052r0 Submission January 2007 Steve Shellhammer, QualcommSlide 20 Available Channel List A list of available channels Sorted from most preferred to least preferred Preference is measured in terms of potential interference –Systems close to but outside the keep-out region would likely be low on the list

21 doc.: IEEE /0052r0 Submission January 2007 Steve Shellhammer, QualcommSlide 21 Available Channel Selection Function The ACSF resides within the WRAN base station The ACSF collect outputs of the SSF in the base station and all the CPEs The ACSF generates the available channel list (ACL)

22 doc.: IEEE /0052r0 Submission January 2007 Steve Shellhammer, QualcommSlide 22 ACSF Input/Output

23 doc.: IEEE /0052r0 Submission January 2007 Steve Shellhammer, QualcommSlide 23 Conclusions The Spectrum Sensing Function has been introduced with the inputs and outputs defined The Available Channel Selection Function has been introduced with its inputs and outputs A first-cut at Acronyms and Definitions has been generated Preliminary specifications for the SSF and the ACSF have been generated

24 doc.: IEEE /0052r0 Submission January 2007 Steve Shellhammer, QualcommSlide 24 Next Steps Generate a document with the details of the SSF and ACSF Review the document with the Sensing Team on conference calls Hold a vote in the WG (hopefully in March) to incorporate the text into the working document


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