Ray,
Sorry for not providing the full example (which is in Section 6.4.2).
The Bw refers a bandwidth that surrounds the entire array. That is, each
Spectrum Profile is associated with a Bandwidth specification (e.g., 6MHz,
8MHz, 100kHz), allowing a regulator to provide different requirements for
different operating modes. There would be one complete profile for each
bandwidth.
A more complete example would be something like the following, where
"spectra" includes multiple spectrum profiles:
"spectra": [
{
"bandwidth": 6e6,
"points": [
{ "freqHz": 4.70e8, "maxPsdDbmPerBw": -56.8 },
{ "freqHz": 5.18e8, "maxPsdDbmPerBw": -56.8 },
{ "freqHz": 5.18e8, "maxPsdDbmPerBw": 30.0 },
{ "freqHz": 5.24e8, "maxPsdDbmPerBw": 30.0 },
{ "freqHz": 5.24e8, "maxPsdDbmPerBw": 36.0 },
{ "freqHz": 5.30e8, "maxPsdDbmPerBw": 36.0 },
{ "freqHz": 5.30e8, "maxPsdDbmPerBw": -56.8 },
{ "freqHz": 6.98e8, "maxPsdDbmPerBw": -56.8 }
]
},
{
"bandwidth": 1e5,
"points": [
{ "freqHz": 4.70e8, "maxPsdDbmPerBw": -74.58 },
{ "freqHz": 5.18e8, "maxPsdDbmPerBw": -74.58},
{ "freqHz": 5.18e8, "maxPsdDbmPerBw": 27.0 },
{ "freqHz": 5.24e8, "maxPsdDbmPerBw": 27.0 },
{ "freqHz": 5.24e8, "maxPsdDbmPerBw": 33.0 },
{ "freqHz": 5.30e8, "maxPsdDbmPerBw": 33.0 },
{ "freqHz": 5.30e8, "maxPsdDbmPerBw": -74.58 },
{ "freqHz": 6.98e8, "maxPsdDbmPerBw": -74.58 }
]
}
]
(note that the example does not match any actual rule, it's just an example
of the encoding)
- The first set of values for maxPsdDbmPerBw represents max power (dBm)
over any 6MHz
- The first set of values for maxPsdDbmPerBw represents max power (dBm)
over any 100kHz
A device must satisfy both.
In this hypothetical example, a device may, for instance, operate 2 100kHz
sub-channels within [518MHz, 524HMz) at 27dBm, but not any more.
- Each sub-channel meets the 100kHz spec
- The sum of the two meets the 6MHz spec
Does that make more sense?
-vince
On Fri, Sep 6, 2013 at 1:29 AM, Ray Bellis <[email protected]>wrote:
>
> On 5 Sep 2013, at 01:23, Vincent Chen <[email protected]> wrote:
>
>
> - The encoding uses an array, for example (thanks for the catch, Dan!):
> [
> { "freqHz": 4.70e8, "maxPsdDbmPerBw": -56.8 },
> { "freqHz": 5.18e8, "maxPsdDbmPerBw": -56.8 },
> { "freqHz": 5.18e8, "maxPsdDbmPerBw": 30.0 },
> { "freqHz": 5.24e8, "maxPsdDbmPerBw": 30.0 },
> { "freqHz": 5.24e8, "maxPsdDbmPerBw": 36.0 },
> { "freqHz": 5.30e8, "maxPsdDbmPerBw": 36.0 },
> { "freqHz": 5.30e8, "maxPsdDbmPerBw": -56.8 },
> { "freqHz": 6.98e8, "maxPsdDbmPerBw": -56.8 }
> ]
>
> - Even for regulatory domains that do not compute a level for all
> channels, there are still generalized (absolute) limits on unintended EM
> emissions, so there should be no need to use special values, such as -inf,
> null, etc. for indicating the "unavailable" ranges.
>
> Should we adopt this more general encoding over the "channelized"
> encoding in Draft 06?
>
>
> I don't like it at all.
>
> The questions I raised about the "Bw" part of "maxPsdDbmPerBw" and the
> exact mechanism of how to encode multiple bandwidth PSDs are still
> unanswered.
>
> It *appears* that "Bw" is supposed to be the delta between the current
> entry and the previous entry? Not only does this result in a potential
> division-by-zero that has to be detected, it would seem that to encode the
> OFCOM/ETSI rules that require a PSD over 100 kHz would require an entry (or
> in fact a pair of entries) for *every single 100 kHz subchannel* within the
> band.
>
> Also, I'm pretty certain that the OFCOM/ETSI model will actually result
> in channels that simply cannot be used. We haven't seen the DTT sample data
> yet but previous conversations have strongly suggested that in certain
> squares they will not permit any transmissions in certain channels. This
> simple contiguous set of power vs frequency points cannot encode that.
>
> Ray
>
>
>
>
--
-vince
_______________________________________________
paws mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/paws
