1. doc.: IEEE 802.18-08/0016r0 Submission March 2008 Rich Kennedy, OakTree WirelessSlide 1 DFS Update from the European Union Date: 2008-3-18 Authors:

2. doc.: IEEE 802.18-08/0016r0 Submission Dynamic Frequency Selection In the EU, EN 301 893 defines regulatory requirements for RLAN operation in the 5GHz band DFS was devised to protect radar operating in that band –Radar and RLANs are co-equal users of the band (EU) –RLANs detecting radar patterns defined by 301 893 must move to a clear channel Weather radar signatures were not included in the initial (or second) version of DFS (v1.3.1 and v1.4.1) The EU has started to receive interference complaints from the meteorological community (EUMETNET)

3. doc.: IEEE 802.18-08/0016r0 Submission EU Weather Radar EUMETNET Report to the Wi-Fi Alliance –Philippe Tristant attended the Prague session –Government weather radar needed to protect populace from serious weather conditions –Serious interference issues seen –Petitioned TCAM to help protect weather radar TCAM decisions –Changes to EN 301 893 in phases –Immediate remedy for the radars – banning RLANs from 5600 – 5650MHz band until new patterns, pulse detection becomes mandatory

4. doc.: IEEE 802.18-08/0016r0 Submission EU Regulatory The TCAM Committee: –is the Telecommunication Conformity Assessment and Market Surveillance Committee –Role is defined within the Directive 1999/5/EC (R&TTE)Directive 1999/5/EC See articles 13 to 15 of the Directive 1999/5/ECarticles 13 to 15 Directive 1999/5/EC –Formal procedures: article 5 provides for safeguards against shortcomings in standards.article 5 The Commission (after opinion of TCAM) can: –Withdraw standards –Interpret standards or give guidelines on the conditions under which they give presumption of conformity –Informal procedures: try to manage issues through consensus TCAM issues Opinions based on proposals made by the representative of the Commission (TCAM Chair) Common understanding on the way forward

5. doc.: IEEE 802.18-08/0016r0 Submission TCAM Decisions Document TCAM24(24) from the EC –Meteo radars interfered by 5 GHz RLAN –EC concluded DFS has shortcomings –Industry need to address these before 5 GHz RLAN technology is suitable for mass market development Staggered PRF Narrower Pulses (0,8 µSec / 0,5 µSec) Solution for noise calibration of weather radars (10 min CAC or equivalent) –only for the band 5600 - 5650 MHz –Other radars have comparable characteristics, hence Staggered PRF and Narrower Pulses should be applied across the whole band. EC conclusions/proposals above endorsed by TCAM

6. doc.: IEEE 802.18-08/0016r0 Submission DFS Changes Now: RLANs can not operate in the 5600 – 5650 MHz band After 3/31/08 must meet EN 301 893 v1.3.1 or 1.4.1 requirements After 6/30/08 must be able to detect staggered PRF (3 PRF values) in 5600 - 5650 MHz band; or block the band (channels 120, 124 and 128) After 3/31/09 must also meet EN 301 893 v1.5.1 requirements: –Detect 0.8uS pulse width across 5250 – 5350 and 5470 – 5725 MHz bands –Detect staggered PRF across 5250 – 5350 and 5470 – 5725 MHz bands –Include a solution for weather radar noise calibration period (10 min CAC) After 6/30/10 must meet EN 301 893 v1.6.1 –All the 1.5.1 requirements –Detect 0.5uS pulse width across 5250 – 5350 and 5470 – 5725 MHz bands

7. doc.: IEEE 802.18-08/0016r0 Submission Proposed Relaxation of the CAC Requirement Non-Continuous Off-Channel CAC (for all DFS channels) –as an alternative for the continuous CAC Scheduled CAC for weather radar channels –Avoid the weather radar band at start up and do a CAC later on or do an Off-Channel CAC while operation has started on a channel outside 5600-5650 CAC time for weather radar band –Full 10 min CAC (or equivalent Off-Channel CAC) only first time a channel in 5600-5650 MHz is being checked. –If no radar found, subsequent CAC checks should only be 60 sec

8. doc.: IEEE 802.18-08/0016r0 Submission Proposed Relaxation of the CAC Requirement [2] Relaxation on the Uniform Spreading requirement –Use 60% of the available spectrum in stead of 80% –Impact is < 1.5 dB Some applications do not require all channels and as such they should not be impacted by the 10 min CAC Relaxation on the Channel Closing Transmission Time –Proposed 1 sec in stead of 260 mSec required for mesh networking, other applications will not need this DFS Threshold level –Threshold level as a function of the Power Density

9. doc.: IEEE 802.18-08/0016r0 Submission Some Things We Can (Should) Do TCAM has set the DOW for version 1.4.1 to 1 April 2009 ETSI should progress the work with the objective to finish revision of EN 301 893 latest mid 2008 –National voting + processing time ETSI + processing time EC > 6 months –Publication in OJEC should be at least a few months prior to the DOW for version 1.4.1 Once ETSI has sent the new EN 301 893 into voting, industry should ask TCAM to revise the 1 April 2009 date and move it e.g. to end of 2009 or mid 2010 –The EC is firm with regard to what should be included in version 1.5.1 –So once we have done 1.5.1 as they requested, we believe we can get a relaxation on the time line to give industry more time to implement 1.5.1 into their products