Primary User Protection in 802.22 Proposals

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					January 2006                                                                                                              doc.: IEEE 802.22-06/0007r0


            Primary User Protection in 802.22 Proposals
                         IEEE P802.22 Wireless RANs                                                                      Date: 2006-01-16
Authors:
Name                                      Company Address                                                                 Phone                               email
Steve Shellhammer Qualcomm                                               5775 Morehouse Dr   (858) 658-1874                                                   Shellhammer@ieee.org
                                                                         San Diego, CA 92121




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Submission                                                                                  Slide 1                                                Steve Shellhammer, Qualcomm
 January 2006                                    doc.: IEEE 802.22-06/0007r0


                Purpose of the Presentation
• In November 2005 ten proposals were submitted to IEEE
  802.22
• Many of these proposals include techniques for protecting
  primary users
     – Primary users in this band refers to DTV and Part 47 devices
     – This is often referred to as “vertical sharing”
     – Similarly, “horizontal sharing” is sharing between systems with equal
       access rights
• This presentation summarizes these protection techniques
• This presentation does not attempt to evaluate the
  proposals, just to summarize
• This presentation does not address other aspects of the
  proposals
 Submission                          Slide 2               Steve Shellhammer, Qualcomm
January 2006                                         doc.: IEEE 802.22-06/0007r0


                        Proposal Documents
 Company                                             Documents
 Communication Research Center (CRC), Canada         22-05-0057r0, 22-05-0063r0
 ETRI, Samsung Electro-magnetics, and Georgia Tech   22-05-0108r0, 22-05-0109r0
 Huawei Technologies                                 22-05-0106r0, 22-05-0107r1
 Institute for Infocomm Research                     22-05-0093r0, 22-05-0094r0
 Nextwave                                            22-05-0091r0, 22-05-0092r0
 Nanotron                                            22-05-0101r0, 22-05-0102r0
 Phillips and France Telecom                         22-05-0103r0, 22-05-0104r0,
                                                     22-05-0105r1
 Samsung                                             22-05-0099r0, 22-05-0100r1
 ST Microelectronics and Runcom                      22-05-0097r0, 22-05-0098r0
 Thompson                                            22-05-0095r0, 22-05-0096r0


Submission                               Slide 3               Steve Shellhammer, Qualcomm
January 2006                                    doc.: IEEE 802.22-06/0007r0


                           CRC Canada

 • The protection mechanism in this proposal is the
   broadcasting of which TV channels are occupied over
   the ATSC-DTV forward link
       – This mechanism is assumed to based on knowledge of the
         geographic location and access to a database of TV channel
         utilization




Submission                          Slide 4              Steve Shellhammer, Qualcomm
 January 2006                                  doc.: IEEE 802.22-06/0007r0


              ETRI/Samsung/Georgia Tech

• Two methods of processing the received signal are
  suggested for generating parameter that can be used to
  decide which TV channels are occupied
     – Coarse – Multi-resolution Spectrum Sensing
     – Fine – Analog Autocorrelation
• It is suggested that all the processing be done in the analog
  domain.
• This is an implementation choice and could equally be
  done in the digital domain



 Submission                         Slide 5             Steve Shellhammer, Qualcomm
 January 2006                                            doc.: IEEE 802.22-06/0007r0


                    ETRI/Samsung/Georgia Tech
Directive Antenna

                            Transmitter
               SW or
                              (RF/IF)                  PHY
              Duplexer                              (Baseband)
                             Receiver
                              (RF/IF)
 Omni Antenna
                                                                          MAC
                                              Sensing Receiver
                              Coarse
                              “MRSS”                Low Speed
                                                      ADC
                               Fine
                              “AAC”



                         Cognitive WRAN Architecture

 Submission                               Slide 6                 Steve Shellhammer, Qualcomm
 January 2006                          doc.: IEEE 802.22-06/0007r0


              Multi-resolution Spectrum Sensing

• It is suggested that the coefficients of the Wavelet
  Transform are generated by correlating the received
  signal with the a given wavelet basis function in the
  analog domain
• The coefficient is converted to digital format using a low-
  speed ADC
• The wavelet basis function is changed to calculate another
  wavelet transform coefficient
• These wavelet transform coefficients are then used to
  decide if a channel is occupied


 Submission                  Slide 7            Steve Shellhammer, Qualcomm
January 2006                                                 doc.: IEEE 802.22-06/0007r0


              Multi-resolution Spectrum Sensing




 x(t)
                           X
                                    z(t)                          y(t)
                                                                            ADC

         Driver Amp     w(t)                               CLK#2


                                           CLK#1
                                                     Timing
                      v(t)*fLO(t)                                                         MAC
                                                      Clock

                       Wavelet
                      Generator

        Block Diagram of Multi-resolution Spectrum Sensing

Submission                                 Slide 8                        Steve Shellhammer, Qualcomm
                        January 2006                                                                                                              doc.: IEEE 802.22-06/0007r0


                                                        Multi-resolution Spectrum Sensing
• Example of spectrum analysis using MRSS

                                 40                                                                                             -50


                                 20                                                                                             -60
Power Spectrum Magnitude (dB)




                                  0                                                                                             -70


                                 -20                                                                                            -80




                                                                                                                    PSD (dB)
                                 -40                                                                                            -90


                                 -60                                                                                           -100


                                 -80                                                                                           -110


                                -100                                                                                           -120
                                       0   0.2   0.4   0.6   0.8        1    1.2   1.4   1.6   1.8          2                         0   0.2   0.4   0.6   0.8     1     1.2   1.4   1.6   1.8          2
                                                                   Frequency                                6                                                Frequency (Hz)                              6
                                                                                                     x 10                                                                                         x 10




                                       The spectrum of the wireless                                                  The corresponding signal spectrum
                                            microphone signal                                                        detected with the MRSS technique


                    Submission                                                                                  Slide 9                                               Steve Shellhammer, Qualcomm
 January 2006                           doc.: IEEE 802.22-06/0007r0


                Analog Autocorrelation
• The autocorrelation of a random process is the expected
  value of the product of the signal and a delayed version of
  the signal
• The proposal suggests calculating the autocorrelation
  function in the analog domain.
• The delay value is varied and the process is repeated
• The low-speed ADC converts the autocorrelation value to
  digital format
• The proposal claims that this technique can be used for
  blind detection
• The proposal states that this can also be used for signal
  classification

 Submission                  Slide 10            Steve Shellhammer, Qualcomm
January 2006                                             doc.: IEEE 802.22-06/0007r0


                          Analog Autocorrelation

    Sensing Antenna



             x(t)
                                                                        Low
                           Multiplication    Integrate    FIR          Speed
                                                                        ADC


              Delay Td
                                  x(t-Td))
                                                                                 Decision
                                                                                  Making



                         Block Diagram of Analog Autocorrelation


Submission                                   Slide 11             Steve Shellhammer, Qualcomm
January 2006                                           doc.: IEEE 802.22-06/0007r0


                 ETRI/Samsung/Georgia Tech

 • The MAC maintains several lists
       –     Set of TV channels used by CPE
       –     Set of TV channels used by base station
       –     Set of five candidate TV channels
       –     Set of occupied TV channels
       –     Set of disallowed TV channels
 • The MAC provides a quiet period for sensing the
   spectrum
       – The lists are update after the sensing period




Submission                              Slide 12                Steve Shellhammer, Qualcomm
January 2006                                     doc.: IEEE 802.22-06/0007r0


              ETRI/Samsung/Georgia Tech

 • The downlink channel descriptor is modified to include
   these lists
 • The MAC includes a procedure for switching channels
       – There seems to be an option for only a subset of the CPEs to
         change channels
 • The CPEs report their sensing results to the BS in
   response to a request




Submission                           Slide 13             Steve Shellhammer, Qualcomm
 January 2006                          doc.: IEEE 802.22-06/0007r0

         Question for ETRI/Samsung/Georgia Tech
• Are MRSS and AAC intended to operate in parallel or in
  series?
• How long does it take to calculate the wavelet transform
  coefficients using this analog technique?
• How are the wavelet transform coefficients from MRSS
  used to decide if a channel is occupied or not?
• Do you have any simulation results showing probability of
  detection and false alarm rate using MRSS?
• How is the autocorrelation function used to decide whether
  the channel is occupied?
• How is AAC used for blind detection? Don’t you need
  some knowledge of the signal to fix your decision rule?
• Do you have any simulation results showing probability of
  detection and false alarm rate using AAC?
 Submission                 Slide 14            Steve Shellhammer, Qualcomm
January 2006                          doc.: IEEE 802.22-06/0007r0


               Huawei Technologies

 • The proposal suggest dividing each TV channel into
   sub-channels
 • It would be possible to populate a subset of sub-
   channels
 • This is intended to reduce interference caused to
   wireless microphones




Submission                 Slide 15            Steve Shellhammer, Qualcomm
 January 2006                                    doc.: IEEE 802.22-06/0007r0


              Institute for Infocomm Research
• Time is allocated after the downlink sub-frame and before
  the uplink sub-frame for spectrum sensing
• The channel is divided into sub-channels which consist of
  48 data sub-carriers
• To avoid interference to wireless microphones some of
  these sub-channels may be nulled out
     – Since the sub-channels may consist of non-adjacent sub-carriers several
       methods are proposed for nulling out a contiguous set of sub-carriers




 Submission                          Slide 16              Steve Shellhammer, Qualcomm
January 2006                                            doc.: IEEE 802.22-06/0007r0


             Institute for Infocomm Research
 • The proposal also includes an option to null out some
   sub-carriers for sensing while transmitting on the
   other sub-carriers
             `
                                                                Configuration I




                                                                Configuration II




                 Pilot subcarrier
                 Control subcarrier
                 Null subcarrier (Sensing)


Submission                                   Slide 17            Steve Shellhammer, Qualcomm
January 2006                            doc.: IEEE 802.22-06/0007r0


               Questions for Infocomm

 • Have you performed any tests to see if nulling out a
   portion of the TV channel will effectively prevent
   interference with wireless microphones operating in
   that part of the TV channel?
 • Have you performed any simulations to demonstrate
   that you can effectively listen on a nulled sub-carrier
   while adjacent sub-carriers are populated?
 • What type of signals (e.g. DTV or wireless
   microphones) can be detected using this approach?



Submission                   Slide 18            Steve Shellhammer, Qualcomm
January 2006                                     doc.: IEEE 802.22-06/0007r0

                               Nextwave
 • The proposal states that the MAC includes a number of
   procedures for managing sharing of the spectrum. The
   listed procedures are,
       – Testing channels for other users including specific spectrum users
       – Discontinuing operations after detecting other users including
         specific spectrum users
       – Detecting other users including specific spectrum users
       – Scheduling for channel testing
       – Requesting and reporting of measurements
       – Selecting and advertising a new channel
 • The proposal does not seem to include the details of
   these procedures

Submission                           Slide 19              Steve Shellhammer, Qualcomm
January 2006                         doc.: IEEE 802.22-06/0007r0


               Questions for Nextwave

 • When can you supply the details of the MAC
   procedures listed in your proposal?




Submission                Slide 20            Steve Shellhammer, Qualcomm
January 2006                          doc.: IEEE 802.22-06/0007r0


                       Nanotron

 • This proposal does not include any material on
   protection of primary users




Submission                 Slide 21            Steve Shellhammer, Qualcomm
January 2006                              doc.: IEEE 802.22-06/0007r0


               Philips and France Telecom

 • PHY Summary
       – Energy Detector
       – Smoothed PSD estimator
       – ATSC detector based on correlation with PN511 signal
 • MAC Summary
       – New Spectrum Management (SM) Layer
       – Support for quiet period
       – Reports on spectrum measurements


Submission                     Slide 22            Steve Shellhammer, Qualcomm
January 2006                               doc.: IEEE 802.22-06/0007r0


               Philips and France Telecom

 • Energy Detector
       – Estimate received signal strength indicator (RSSI)
       – Estimate noise power
       – Detector compares RSSI and scaled version of the
         noise power estimate




Submission                      Slide 23            Steve Shellhammer, Qualcomm
January 2006                             doc.: IEEE 802.22-06/0007r0


               Philips and France Telecom

 • Part 74 Feature Detector
       – Using the FFT from the OFDMA PHY calculate the
         periodogram as an estimate of the power spectral
         density
       – Then calculate the mean and variance of the PSD
       – The detector then compares the PSD with a linear
         function of the mean and variance
       – This allows detecting non-uniformity of the PSD



Submission                    Slide 24            Steve Shellhammer, Qualcomm
January 2006                              doc.: IEEE 802.22-06/0007r0


               Philips and France Telecom

 • ATSC DTV Feature Detector
       – The received signal is correlated with the know PN511
         signal
       – The running mean and variance of the correlator output
         are calculated
       – The detector compares the variance with a scaled
         version of the mean




Submission                     Slide 25            Steve Shellhammer, Qualcomm
January 2006                              doc.: IEEE 802.22-06/0007r0


               Philips and France Telecom

 • Cognitive MAC (CMAC)
       – Scheduled quiet periods for spectrum sensing
       – A CPE can perform in-band sensing during a quiet
         period
       – A CPE can perform out-of-band sensing either during a
         quiet period or outside of a quiet period
       – There is a mechanism for base stations to attempt to
         synchronize their quiet periods with overlapping
         WRAN cells, to improve spectrum sensing


Submission                     Slide 26            Steve Shellhammer, Qualcomm
January 2006                               doc.: IEEE 802.22-06/0007r0


               Philips and France Telecom

 • Cognitive MAC Frames
       – MAC Frames sent by the base station to request the
         CPE performs spectrum sensing and reports results
       – Two types of measurement reports: regular and urgent
       – Regular reports send measurement results to base
         station on a regular interval
       – An urgent report is sent to indicate that a primary user
         has been detected by the CPE in the occupied TV band



Submission                      Slide 27            Steve Shellhammer, Qualcomm
January 2006                               doc.: IEEE 802.22-06/0007r0


               Philips and France Telecom

 • Cognitive MAC Frames
       – If the CPE has allocated TX time then after a quiet
         period the CPE reports an abbreviated report in a
         measurement frame specifying which TV channels are
         occupied
       – Subsequently the BS can then request more detailed
         measurement reports
       – If the CPE does not have allocated TX time then there
         is a Urgent Coexistence Situation (UCS) time slot that
         can be used to transmit the urgent abbreviated report

Submission                      Slide 28            Steve Shellhammer, Qualcomm
January 2006                               doc.: IEEE 802.22-06/0007r0


               Philips and France Telecom

 • Cognitive MAC Frames
       – The UCS notification slot can be accessed either using
         a contention-based protocol, like CSMA/CA or it can
         use a contention-based CDMA mechanism using a
         randomly selected code
       – If the BS does not receive a report from the CPE it may
         be due to interference from an in-band primary user
       – Under this condition the BS shall infer that the channel
         is occupied by a primary user and change to another
         channel

Submission                      Slide 29            Steve Shellhammer, Qualcomm
January 2006                                      doc.: IEEE 802.22-06/0007r0


                 Philips and France Telecom
 • Cognitive MAC Frames
       – There are multiple messages for reporting spectrum
         sensing results
             • MAC Frames for reporting measurement statistics
             • MAC Frame for reporting only the results of the detection
               algorithm specifying which channels are occupied and which
               are not
             • Subfields in the MAC header to indicate a UCS and which
               channel in which it was detected
       – By maintaining a list of backup channels, at BS and
         CPEs, the proposal supports recovery from the
         detection of an in-band primary user

Submission                            Slide 30             Steve Shellhammer, Qualcomm
January 2006                           doc.: IEEE 802.22-06/0007r0


         Questions for Philips and France Telecom

 • Do you have any simulation results for the three
   detectors suggested in this proposal?




Submission                  Slide 31            Steve Shellhammer, Qualcomm
 January 2006                                  doc.: IEEE 802.22-06/0007r0


                              Samsung
• The proposal emphasizes the need for distributed sensing
• The proposal correctly identifies that the distributed
  sensing information must be fused together at the base
  station
     – Data Fusion: Combining processed information to make centralized
       decision
     – Decision Fusion: Combine localized decisions into a centralized
       decision
• The authors state that the data fusion and decision fusion
  architectures are fairly independent of the individual
  decision algorithms employed at the CPEs


 Submission                        Slide 32             Steve Shellhammer, Qualcomm
January 2006                              doc.: IEEE 802.22-06/0007r0


                          Samsung

 • The authors identify that the WRAN is solving
   a distributed Hypothesis Testing problem.
 • The proposal suggest two types of detectors
       – Energy Detector
       – Cyclostationary Detector
 • The proposal assumes that the samples of the
   received signal are independent



Submission                     Slide 33            Steve Shellhammer, Qualcomm
 January 2006                          doc.: IEEE 802.22-06/0007r0


                        Samsung
• The authors point out that energy detection is a good
  approach when you do not have any a priori information
  about the signal
• The authors point out that energy detection is optimum for
  detecting Gaussian signal in additive white Gaussian noise
• For data fusion in the energy detector the proposal
  suggests summing the individual sensed energy values and
  using that sum as the decision statistic




 Submission                 Slide 34            Steve Shellhammer, Qualcomm
January 2006                      doc.: IEEE 802.22-06/0007r0


                    Samsung

 • For decision fusion based the authors suggest
   summing the individual decisions from each of
   the CPEs an comparing that sum-of-decisions
   to a threshold to calculate the centralized
   decision




Submission             Slide 35            Steve Shellhammer, Qualcomm
January 2006                            doc.: IEEE 802.22-06/0007r0


                         Samsung
• The proposal gives some background on cyclostationary
  processes
• The authors state that the cyclostationary detector does
  not have the problem with noise that the energy detector
  has, since detection can theoretically be done irrespective
  of the noise power level
• Energy detection is a special case of cyclostationary
  detector, since the power spectral density is a subset of the
  spectral correlation density function



Submission                   Slide 36            Steve Shellhammer, Qualcomm
January 2006                            doc.: IEEE 802.22-06/0007r0


                         Samsung

 • One of the advantages of using the cyclostationary
   detector is the fact that it can be used for both detection
   and classification
 • Another advantage of the cyclostationary detector is
   that it is extensible to be able to handle new signals that
   may be introduced in the band in the future




Submission                   Slide 37            Steve Shellhammer, Qualcomm
January 2006                            doc.: IEEE 802.22-06/0007r0


               Questions for Samsung

 • Why do you believe that the data fusion and decision
   fusion architectures are fairly independent of the
   individual decision algorithms employed at the CPEs?
 • How can you assume that the samples of the received
   signal are independent?
 • What practical issues arise due to detection of a signal
   corrupted by noise using a cyclostationary detector?




Submission                   Slide 38            Steve Shellhammer, Qualcomm
January 2006                              doc.: IEEE 802.22-06/0007r0


                 ST Micro and Runcom

 • This proposal describes the trade-offs in
   allocating time for quiet periods for spectrum
   sensing
       – Spectrum sensing can be performed reliably without
         interference caused by WRAN transmissions
       – The sensing period will increase latency over the
         WRAN network
       – The sensing period will decrease WRAN network
         latency


Submission                     Slide 39            Steve Shellhammer, Qualcomm
January 2006                                         doc.: IEEE 802.22-06/0007r0


                        ST Micro and Runcom
• The proposal suggests three methods of
  scheduling spectrum sensing
    – Non-overlapping with data transmissions
             • Sensing is only performed during quiet periods
    – Full-overlap with data transmissions
             • Sensing can be performed during data transmissions
    – Selective-overlap with data transmission
             • Sensing can be performed on selective channels during data
               transmission




Submission                               Slide 40               Steve Shellhammer, Qualcomm
January 2006                                                        doc.: IEEE 802.22-06/0007r0


                          ST Micro and Runcom

• Selective-overlap sensing
    – If a channel has enough frequency separation from the
      utilized channel it is possible to perform reliable sensing
      on that channel during data transmission

        Spectrum being sensed   Spectrum gap   Spectrum in use   Spectrum gap   Spectrum being sensed




                                                Frequency




Submission                                       Slide 41                       Steve Shellhammer, Qualcomm
 January 2006                           doc.: IEEE 802.22-06/0007r0


                ST Micro and Runcom
• The proposal suggests that the WRAN use dynamic
  frequency hopping (DFH)
• After the sensing period the BS selects one of the available
  TV channels and network hops to that channel for a
  specified time.
• How long the network dwells on each TV channel can be
  changed dynamically
• By changing operating frequency the set of TV channels
  that cannot be sensed during data transmission changes,
  which improves spectrum sensing


 Submission                  Slide 42            Steve Shellhammer, Qualcomm
January 2006                                       doc.: IEEE 802.22-06/0007r0


                    ST Micro and Runcom

 • Since two neighboring WRAN cells could potentially
   select the same channel the proposal introduces a
   method of avoiding this event
       – One cell waits until the adjacent cell selects it new operating
         frequency
       – It decodes the message from the adjacent BS
       – Then it selects a different operating frequency
 • This method required adjacent BS to be able to decode
   messages from each other



Submission                            Slide 43               Steve Shellhammer, Qualcomm
January 2006                                                                  doc.: IEEE 802.22-06/0007r0


                          ST Micro and Runcom
                                           Operating on CH A                Operating on CH B
                                          Sensing on CH ([0, A-n],        Sensing on CH ([0, B-n],
                                                 [A+n, N])                       [B+n, N])

                                                          Validation time of CH B
               Validation time of CH A
                                                                     Validation time of CH C


       System A
                                                                                                          Time
                                                                      Announce to use CH C
             Validation time of CH D       Validation time of CH C
                                                                               Collision free

       System B
                                           Operating on CH D              Operating on CH C               Time
                                         Sensing on CH ([0, D-n],       Sensing on CH ([0, C-n],
                                                [D+n, N])                      [C+n, N])




Submission                                              Slide 44                                Steve Shellhammer, Qualcomm
January 2006                                       doc.: IEEE 802.22-06/0007r0


                    ST Micro and Runcom
 • Sensing reports can be in one of two forms
       – Bit vector reports specifying one of four states of the channel:
          • Occupied by a licensed system
          • Occupied by another 802.22 system
          • Noisy
          • Vacant
       – Raw data reports transmit the raw data
 • The proposal describes several methods for scheduling
   the reporting
       – Polling
       – Poll-me
       – Contention


Submission                            Slide 45              Steve Shellhammer, Qualcomm
January 2006                         doc.: IEEE 802.22-06/0007r0


         Questions for ST Micro and Runcom

 • How many TV channels need to be available for use
   so that dynamic frequency hopping can be used
   effectively?
 • What does the WRAN network do if there is
   insufficient available TV channels?




Submission                Slide 46            Steve Shellhammer, Qualcomm
January 2006                              doc.: IEEE 802.22-06/0007r0


                            Thompson

 • The proposal describes dynamic frequency selection
   (DFS) as required in 802.22
 • The proposal recommends utilizing quiet periods for
   sensing
 • The proposal recommends techniques for detecting
   ATSC DTV signals
       – Sensing Method 1
       – Sensing Method 2




Submission                     Slide 47            Steve Shellhammer, Qualcomm
January 2006                                doc.: IEEE 802.22-06/0007r0


                           Thompson

 • Sensing Method 1
       – First step is to detect the pilot using filtering and PLL
       – Using pilot down convert to baseband
       – Use a matched filter on the PN511 sequence
       – As an alternative use a matched filter on the PN63
         sequence
       – The proposal also lists several other signal features that
         can be used to detect the ATSC DTV signal



Submission                       Slide 48            Steve Shellhammer, Qualcomm
January 2006                              doc.: IEEE 802.22-06/0007r0


                         Thompson

 • Sensing Method 2
       – This method does not require extracting the pilot
       – A complex autocorrelation is performed
       – The detector identifies peaks in the autocorrelation
         signal
       – The autocorrelation signal may be smoothed using an
         IIR digital filter




Submission                     Slide 49            Steve Shellhammer, Qualcomm
January 2006                           doc.: IEEE 802.22-06/0007r0


                      Thompson

 • The proposal introduces a novel method for improving
   the estimate of timing an frequency by utilizing the
   received signal from a stronger DTV station
 • This method relies on the tight frequency tolerances in
   DTV
       – 1 KHz




Submission                  Slide 50            Steve Shellhammer, Qualcomm
 January 2006                                     doc.: IEEE 802.22-06/0007r0


                              Thompson
• The proposal includes recommendations on the design of
  the omnidirectional sensing antenna
     – Concern is raised about the difficulty in designing an omni antenna that
       operates over the entire UHF band without spatial nulls
     – The proposal suggests using two antennas and alternating sensing.
       This eliminates the nulls at the cost of twice the time required for
       sensing
• The proposal also includes a recommendation on the
  design of a device that can be used to detect if the antenna
  is not properly aligned



 Submission                          Slide 51              Steve Shellhammer, Qualcomm
January 2006                           doc.: IEEE 802.22-06/0007r0


               Questions for Thompson

 • Do you have any simulation results for the two sensing
   methods you proposed?




Submission                  Slide 52            Steve Shellhammer, Qualcomm
January 2006                       doc.: IEEE 802.22-06/0007r0


                    Summary

 • This proposal attempts to summarized the
   portion of each proposal that addresses
   protection of primary users
 • There is a follow-up presentation on Cognitive
   Radio Framework for Protection of Primary
   Users




Submission              Slide 53            Steve Shellhammer, Qualcomm