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5GHz and Weather Radars

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					September 2007                                                                                                            doc.: IEEE 802.18-07/0077r0


  5GHz RLANs and the Spectrum Challenges from
         the Weather Radar Industry

                                                                         Date: 2007-09-18

Authors:
Name                               Company                                     Address                          Phone                            email
                                                                                                                                                 rich.kennedy@oaktreewireless.com
Rich Kennedy                       OakTree Wireless                            Austin, TX                       281-222-6299



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Submission                                                                                  Slide 1                                             Rich Kennedy, OakTree Wireless
                                                     doc.: IEEE 802.18-07/0077r0


                    DFS and Weather Radar

 • Radio Regulations for RLANs in 5470 – 5725MHz
   band require DFS for interference avoidance
 • Weather radar in the 5600 – 5650MHz band has
   experienced significant interference
       – Initial blame was placed on non-compliant APs
       – Analysis showed that even compliant devices could not avoid
         some radars
             • Staggered PRF
             • Interleaved PRF
             • Narrow pulse (<1uS)
       – EUMETNET asked TCAM to block the use of this 50MHz of spectrum


Submission
                                                          doc.: IEEE 802.18-07/0077r0


                   TCAM October 1st Ad Hoc
 •    EUMETNET letter to TCAM
       – They realize that their radars and not comprehended by EN 301 893
       – They “…assume that the RLAN industry would be able to find relevant technical
         solutions…”
       – They know that the ETSI process takes time
             • ~1 year to approve a new version
             • 18 months before it becomes mandatory
 • WFA letter to TCAM suggesting:
       – Modify Annex D of EN 301 893 to include
             • Single pulse based staggered PRF (maximum 3 different PRFs with a
               minimum number of pulses (depending on PRF) for each PRF)
             • Packet based staggered PRF (maximum 2 different PRFs with a
               minimum number of pulses (depending on PRF) for each PRF)
       – Modify annex D so that the min pulse width is reduced from 1 uSec to 0,8 uSec (for
         both constant PRF and staggered PRF radar signals)
       – Work with TCAM to see that this is done to everyone’s satisfaction
Submission
                                                                  doc.: IEEE 802.18-07/0077r0


             Various Regulatory Domain Actions

 • Canada RS-210
       – Block the 5600 – 5650MHz band for the time being
       – WFA is asking them to consider alternative approach
              • 0.8uS pulse detection
              • 10 min Channel Availability Check
                 – All client devices have to change for spectrum notch
                 – Only AP required to change CAC
 • Japan requiring DFS test changes
       – 0.5uS pulse detection
       – 50% network loading for some tests
 • Others
       – Korea in the works
       – Australia asked meteorologists the tell them what they want
       – Others?

Submission
                                      doc.: IEEE 802.18-07/0077r0


                    Questions?

 • What should 802.18 do?




Submission                  Slide 5           Rich Kennedy, OakTree Wireless

				
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