On 4/15/2014 5:13 PM, Tom DeReggi wrote:
> Excellent Summry. Can you clarify.....
>
> In previous ISM/UNII 5.750-5.850Ghz, the 2 to1 rule was allowed similar to
> 2.4Ghz, so that 5.8GHZ CPEs in Point-to-MultiPpoint systems could transmit
> at PTP EIRP (higher than the AP 36db EIRP limit) as long as it was
> increased
> via antenna gain. Does that still apply for the new UNII 5.750-5.850Ghz
> rules?
Under the old "ISM" rules for 5725-5850, there was no EIRP limit for
point to point:
(ii) Systems operating in the 5725-5850 MHz band that are used
exclusively for fixed, point-to-point operations may employ
transmitting antennas with directional gain greater than 6 dBi without
any corresponding reduction in transmitter conducted output power.
Under the ISM rules for 2400-2483.5 MHz, there is a 1 for 3 rule, so you
can keep 2/3 of the EIRP above +36 that comes from antenna gain:
(i) Systems operating in the 2400-2483.5 MHz band that are used
exclusively for fixed, point-to-point operations may employ
transmitting antennas with directional gain greater than 6 dBi provided
the maximum conducted output power of the intentional radiator is
reduced by 1 dB for every 3 dB that the directional gain of the antenna
exceeds 6 dBi.
Under the old U-NII rules for 5725-5825, there was an EIRP limit on
point to point that was higher than the +36 dBm limit for point to
multipoint.
For fixed, point-to-point U-NII transmitters
that employ a directional antenna gain greater than 23 dBi, a 1 dB
reduction in peak transmitter power and peak power spectral density for
each 1 dB of antenna gain in excess of 23 dBi would be required.
So the old EIRP point to point limit under U-NII was +53 dBm. The FCC
proposed making that the new unified rule, but -- WISPA and members to
the rescue! -- ended up adopting the ISM "no EIRP limit" instead. Get
those Rocket dishes out... but only above 5725.
(BTW, "ISM" refers to Part 18 RF heaters. 15.247 is the unlicensed
intentional radiators using bands where ISM is the primary user of the
frequency, hence the nickname.)
> I saw that you inferred that that was not likely allowed for the new
> outdoor
> use of Unii 5.1 Ghz.
Correct. The 5150-5250 U-NII-1 segment inherits the old U-NII-3 rule
that everybody got around via the ISM rule (boy is that confusing),
capping EIRP at +53. The new 5150-5250 fixed rule:
For fixed point to-point transmitters that employ a directional antenna
gain greater than 23 dBi, a 1 dB reduction in maximum conducted output
power and maximum power spectral density is required for each 1 dB of
antenna gain in excess of 23 dBi.
>
>> ----- Original Message -----
>> From: "Fred Goldstein" <[email protected]>
>> To: "WISPA General List" <[email protected]>
>> Sent: Friday, April 04, 2014 12:25 PM
>> Subject: [Spam] [WISPA] New FCC rules for 5 GHz bands
>>
>>
>>> On Monday, the FCC formally adopted a First Report and Order (FCC 14-30)
>>> in ET Docket 13-49, revision of Part 15 U-NII rules. The actual R&O
>>> text was released later in the week. For the most part, it came out
>>> well for WISPs. Some rules have been tightened to reduce the chance of
>>> interference to radar, especially TDWR, but more spectrum has been
>>> opened to outdoor use. Note that this was not the final word on 13-49.
>>> It focused on the U-NII-1 band (5150-5250) and U-NII-3 band
>>> (5725-5825). The proposed new U-NII-2B and U-NII-4 bands were not
>>> addressed. Those are more controversial and await a later R&O.
>>>
>>> Key changes that were announced:
>>>
>>> The 5725-5850 ISM band (Rules Part 15.247) was essentially merged with
>>> U-NII-3 (15.407). The upper band edge of U-NII-3 was moved from 5825 to
>>> 5850 to match ISM. Wideband digital operation was removed from ISM,
>>> limiting 15.247 operation on that band to frequency hopping spread
>>> spectrum (narrowband) and the FH portion of hybrid devices. As of one
>>> year after publication in the Federal Register, no new 15.247 wideband
>>> devices will be type-approved for that band, and sale and importation
>>> must stop in two years. Existing devices may continue to be used.
>>>
>>> The WISP community did dodge a bullet here, as the new U-NII-3 rules are
>>> closer to the ISM rules than to the old U-NII rules. In particular, the
>>> proposal to limit EIRP of fixed point-to-point links to +53 dBm, the old
>>> U-NII-3 limit which did not apply to ISM, was not adopted. Fixed
>>> point-to-point U-NII-3 operation can still have unlimited antenna gain
>>> with 1 watt transmitter power. Some of the credit goes to WISPA, who is
>>> acknowledged in the Order. (Cambium too, while its former parent
>>> Motorola Solutions was on the wrong side.) Power spectral density rules
>>> were also modified to a favorable outcome. The old U-NII-3 rules
>>> required 20 MHz bandwidth for full power. The new rules are closer to
>>> ISM's, requiring a minimum 6 dB bandwidth of only 500 kHz for full
>>> power. Point to multipoint EIRP is still capped at +36 dBm. So there
>>> is little lost in the new rules, although the new type approval
>>> procedures will be just a bit harder than the old ones.
>>>
>>> The second major area of change was the U-NII-1 band, 5150-5250. This
>>> had been limited to indoor only use with a +17 dBm power limit.
>>> Globalstar, the low-earth-orbit satellite, is the primary user here,
>>> using it for backhaul (not handset) uplinks, and while LEOsats in
>>> general did not catch on as the FCC had expected when the old rule was
>>> written in 1997, Globalstar did not want its background noise level to
>>> be impacted. A deal was worked out that is still pretty good.
>>>
>>> Under the new rules, outdoor operation is now allowed, and the rules
>>> there are based on the old U-NII-3 rules. So the power limit is 1 watt,
>>> and access points may have up to 6 dB gain without lowering power (i.e.,
>>> a +36 dBm EIRP cap). Point-to-point links may have up to 23 dB gain
>>> without lowering power (i.e., a +53 dBm EIRP cap). "Mobile and portable
>>> client devices" in that band are capped at 250 mW (+24) with 6 dB gain
>>> (i.e., a +30 dBm EIRP cap). There is no explicit rule for fixed client
>>> devices, like WISP CPE, so it appears to be treated as portable, as the
>>> definition of "fixed, point-to-point" explicitly excludes
>>> "point-to-multipoint systems". This could be rather limiting and might
>>> merit a little ex parte discussion with the Friendly Candy Company. The
>>> rule was written with WiFi access points (is CableWiFi messing up the
>>> spectrum in your neighborhood too?) in mind.
>>>
>>> In order to protect Globalstar, outdoor U-NII-1 access points have to be
>>> sure their EIRP more than 30 degrees above the horizon does not exceed
>>> +21 dBm. This seems pretty easy, unless say you're doing a steep
>>> point-to-point shot upwards at a skycraper. Another rule requires
>>> operators who install more than 1000 outdoor U-NII-1 APs to notify (by
>>> letter) the FCC and acknowledge that they will take corrective action if
>>> it does interfere with licensed users. So the average WISP won't be
>>> affected but big cable-style or city-wide deployments could have to
>>> notify.
>>>
>>> Minor changes were made for U-NII-2 (5250-5350 and 5470-5725), were DFS
>>> is required. The radar test procedures were slightly changed. A very
>>> useful rule change is that DFS hopping no longer has to be uniform. The
>>> radio can operate on a selected first-choice frequency until it detects
>>> radar, and then hop to a selected alternative, etc. So band planning is
>>> now legally possible on the DFS bands. Note that proposals to create a
>>> geographic database for U-NII frequencies (like TVWS), as an alternative
>>> to radar sensing, were rejected.
>>>
>>> Type approval for all U-NII equipment now requires that it be locked to
>>> US specifications, so that users can't just turn off DFS or operate
>>> outside of authorized frequencies. Manufacturers can choose the method
>>> for enforcing how only approved software upgrades can be installed.
>>> Certain upgrades of existing gear will be permitted for two years
>>> without meeting all of the new rules, but not afterwards.
>>>
>>> So it seems to me that UBNT and Cambium gear should be all good to go on
>>> the new frequencies pretty quickly, as they are U-NII approved. I don't
>>> think MikroTik is (it's apparently ISM, not DFS approved here, unless
>>> they've recently gotten it), so their radios will need new approval, and
>>> the more restrictive software, in order to stay on sale here after two
>>> years, let alone operate on the newly-authorized outdoor frequencies.
>>>
>>> All told the rules are a positive outcome. Congratulations to everyone
>>> who helped influence the FCC.
>>>
>>> --
--
Fred R. Goldstein k1io fred "at" interisle.net
Interisle Consulting Group
+1 617 795 2701
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