On 02/25/2015 11:17 PM, Peter Oh wrote:
Add support for new FCC DFS rules released on August 14, 2014.
FCC has added a new radar type named Radar Type 1 and original
Radar Type 1 is renamed to Radar Type 0 in consequence.
In fact, the type ID does nothing to functionalities.
In other words, even if we re-order the IDs, DFS detection will
work as well, but we give the ID with matching to FCC doc.
By adding this support, the drivers using this DFS function are
able to support both of old and new FCC DFS rules simultaneously
without any other changes.
[...]
Peter,
while trying to solve detection of the special FCC type 1 radar pattern
with the
pri_detector at hand is a valid approach, it is neither suitable nor
effective.
It is not suitable because in the way you do, it will not reach the
required
detection probability required to pass certification. This is because you
take the
very first pri to configure its detector specs, which is way too
optimistic. You
have to consider that the detector must be able to detect properly with
only 50%
of the pulses seen. In this particular case, you would ignore a lot of
type 1
patterns, since the resulting visibility gap causes temporary false PRIs
that
won't be considered. You might want to have a look on my slides 15ff in
[1] for an
idea what needs to be handled.
Generally, to reach the detection probability requirements, the design of
the
PRI-detector at hand follows a full-coverage search with fast cancellation
approach. For that, it allows collecting potential pattern candidates and
a
posteriori correction of initial assumptions. It is specifically targeting
at
radar patterns defined through PRI-ranges, where constant PRI-ranges are
supported
as special cases by setting the same values for pri_min and pri_max (as is
done
for pattern 0). With support for PRI-ranges and unique PRIs, everything
needed to
detect pattern 1 is there, but defining it as a PRI-range over all the
unique 23
PRIs is the wrong way.
The correct approach is more simple, robust, and efficient: define all
those 23
unique PRIs as sub-patterns for type 1 with individual specs. Would look
like:
#define TYPE1_PPB(X) ((19 * 100000) / (36 * X))
static const struct radar_detector_specs fcc_radar_ref_types[] = {
FCC_PATTERN(0, 0, 1, 1428, 1428, 1, 18, false),
FCC_PATTERN(101, 0, 1, 518, 518, 1, TYPE1_PPB(518), false),
FCC_PATTERN(102, 0, 1, ..., ..., 1, ..., false),
[...],
FCC_PATTERN(123, 0, 1, 3066, 3066, 1, TYPE1_PPB(3066), false),
FCC_PATTERN(2, 0, 5, 150, 230, 1, 23, false),
FCC_PATTERN(3, 6, 10, 200, 500, 1, 16, false),
FCC_PATTERN(4, 11, 20, 200, 500, 1, 12, false),
FCC_PATTERN(5, 50, 100, 1000, 2000, 1, 1, true),
FCC_PATTERN(6, 0, 1, 333, 333, 1, 9, false),
};
Hope it helps, and sorry I didn't do myself, but so far we are only
working in
ETSI domains and ignored FCC completely.
