doc.: IEEE 802.18-08/0016r0

Submission

March 2008

Rich Kennedy, OakTree WirelessSlide 1

DFS Update from the European Union

Date: 2008-3-18

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

Authors:

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)

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

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)

• See articles 13 to 15 of the Directive 1999/5/EC– Formal procedures: article 5 provides for safeguards against

shortcomings in standards. • 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

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

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

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

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

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