"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”
What is the assumed transmitter power? 30dBm? On Apr 15, 2014, at 3:55 PM, Fred Goldstein <fgoldst...@ionary.com> wrote: > 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" <fgoldst...@ionary.com> >>> To: "WISPA General List" <wireless@wispa.org> >>> 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 > > _______________________________________________ > Wireless mailing list > Wireless@wispa.org > http://lists.wispa.org/mailman/listinfo/wireless _______________________________________________ Wireless mailing list Wireless@wispa.org http://lists.wispa.org/mailman/listinfo/wireless
