Patrick Leary writes:
> Ivan, et al,
> No, that is not true (unless you said PTP in error). The 36dB (4 watts)
> limit applies to PMP, and then only for ISM 2.4GHz and ISM 5.725-5.850GHz.
> For UNII (which has 100MHz of band overlapping in upper 5GHz) and also
> covers bands ranging now from 5.15-5.825GHz) has distinct rules, and even
> they vary relative to specific ranges. In any event, no band in UNII exceed
> 36dB from the base station. Also, in 900MHz, the 36dB applies as well to
> PTP.
While the part about 900MHz is true, the preceeding words about 5GHz
are not. U-NII-3 (5.725 - 5.825) allows 30dBm of tx power with 23dBi
of antenna gain. Thats 53dBm EIRP when used for PTP applications.
I quote here from 47 CFR 15.407:
(3) For the band 5.725-5.825 GHz, the peak transmit power over the
frequency band of operation shall not exceed the lesser of 1 W or 17 dBm
+ 10logB, where B is the 26-dB emission bandwidth in MHz. In addition,
the peak power spectral density shall not exceed 17 dBm in any 1-MHz
band. If transmitting antennas of directional gain greater than 6 dBi
are used, both the peak transmit power and the peak power spectral
density shall be reduced by the amount in dB that the directional gain
of the antenna exceeds 6 dBi. However, fixed point-to-point U-NII
devices operating in this band may employ transmitting antennas with
directional gain up to 23 dBi without any corresponding reduction in the
transmitter peak output power or peak power spectral density. 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. Fixed, point-to-point operations exclude the use of
point-to-multipoint systems, omni directional applications, and multiple
collocated transmitters transmitting the same information. The operator
of the U-NII device, or if the equipment is professionally installed,
the installer, is responsible for ensuring that systems employing high
gain directional antennas are used exclusively for fixed, point-to-point
operations.
> The PTP rules for the rest of the ISM foollow what is often called the 3 to
> 1 rule. For every 1 dBm (the m refers to active power, like the hardware or
> an amp) drop, you can raise the dBi (passive gain, like an antenna) by 3dB.
> And when you know that every 3dB gain is double and every 3dB down is half,
> you can get a feel of the significance of such a rule. More to the point,
> you will understand the vast disappointment in the BWA industry when the FCC
> opened up the recent additional 255MHz between 5.47GHz and 5.725GHz, but
> only allowed the power rules of mid UNII, which is 1 watt (30dB) and UNII
> has no 3 to 1 rule. That means folks like Vivato and Navini cannot make or
> market their systems for those bands since their systems are 100% predicated
> on the use of the 3:1 rule at the base station. It also means the effective
> range of all our offerings from 5.25GHz to 5.725GHz will have very short
> range, perhaps to 2 miles, but not even then at higher order modulations
> likely, especially in an NLOS environment.
Also note quite true:
The 3:1 rule applies for 2.4GHz, but not the 5GHz ISM band. The 5GHz
ISM band (5.725 - 5.850) allows up to 30dBm tx power into *unlimited*
antenna gain. I quote here from 47 CFR 15.247:
(3) Except as shown in paragraphs (b)(3) (i), (ii) and (iii) of this
section, if transmitting antennas of directional gain greater than 6 dBi
are used the peak output power from the intentional radiator shall be
reduced below the stated values in paragraphs (b)(1) or (b)(2) of this
section, as appropriate, by the amount in dB that the directional gain
of the antenna exceeds 6 dBi.
(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
peak 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.
(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 peak output power.
(iii) Fixed, point-to-point operation, as used in paragraphs
(b)(3)(i) and (b)(3)(ii) of this section, excludes the use of point-to-
multipoint systems, omnidirectional applications, and multiple co-
located intentional radiators transmitting the same information. The
operator of the spread spectrum intentional radiator or, if the
equipment is professionally installed, the installer is responsible for
ensuring that the system is used exclusively for fixed, point-to-point
operations. The instruction manual furnished with the intentional
radiator shall contain language in the installation instructions
informing the operator and the installer of this responsibility.
Also, the rules for 5.470 - 5.725 include other requirements (TPC and DFS).
> The reason this happened is becasue these rules were essentially made in
> secret with the DoD, the NTIA, and the WLAN industry, though the NTIA likes
> to say they invited industry to participate.
Actually they did. The DoD was (ahem) "quite specific" about the
requirements. I think I've said so on this list before. Check the
archives. There is also a quite open group run by Charles Glass where
most of this gets hashed out.
The FCC had promissed several of us PTP rules for the new spectrum,
you weren't the only one dissapointed. Trust me.
> Only problem is that they did not tell anyone in the BWA space
> because they did not (and still do not entirely) understand the
> distinction between the last mile and the last 100
> meters. Accordingly, no BWA vendors participated in the process. The
> WLAN industry was very happy, though -- they don't want interference
> from long range/last mile BWA systems.
Oh please. Maybe they understand that fixed wireless won't scale.
Note for instance that it is the BWA vendors who have everything to
fear from ubiquitous Wi-Fi. There are a *lot* more APs than
basestations in the world, and they likely surround your CPE as well.
> For the record, if you are deploying for broadband, then every dollar you
> spend on WLAN equipment supports lobbying efforts to scuttle the needs of
> BWA operators like WISPs.
"A vast, right-wing conspiracy exists..." You sound like Hillary, and
you're making me laugh.
I find it interesting that you are so ill-informed on part 15's rules,
yet you're willing to spout off in public about statements that can't
be supported (secret meetings, supposed meetings that included Vivato
counsel, etc.)
What is an "assitant vice president", anyway?
Vivato wasn't granted a "rare exception", either. In fact, the NPRM
that is out will codify a looser system than Vivato would ever design.
Jim
(who just left Vivato)
> I hope this helps.
>
> Regards,
>
> Patrick Leary
> Assistant VP, Marketing
> Alvarion, Inc.
> ph. 760.517.3114
> fax 760.517.3200
> [EMAIL PROTECTED]
>
>
> -----Original Message-----
> From: Ivan Bojer [mailto:[EMAIL PROTECTED]
> Sent: Friday, January 30, 2004 1:13 PM
> To: Patrick Leary; Wireless
> Subject: RE: [BAWUG] Vivato and FCC part 15
>
>
> Now it makes much more sense! Can you maybe confirm if
> cap for all other P2P systems is 36dBm EIRP according to
> current FCC regulations?
>
> -----Original Message-----
> From: Patrick Leary [mailto:[EMAIL PROTECTED]
> Sent: Friday, January 30, 2004 1:01 PM
> To: 'Ivan Bojer'; Wireless
> Subject: RE: [BAWUG] Vivato and FCC part 15
>
>
> Vivato was granted a rare exception in terms of their certification based on
> the theory that their base stations antennas apply some intelligence in
> terms of their directionality toward the specific CPE being talked to. I can
> also tell you that the exception has no logical scientific rational, in that
> the same thing can be achieved mechanically and even then in no way reduces
> the levels of emissions into the cell (which was partly behind the intial
> rules in the first place).
>
> The FCC was trying to spur innovation and stretch the boundaries, but they
> also know they are on shaky legal grounds here. I know this from direct
> meeting with top level folks there. One such meeting was jointly attended
> with Vivato and WCA LEA's legal counsel. The FCC know they could very likely
> lose a legal battle should a competing vendor decide to confront the issue.
> None wish to do so as far as I know though, since partly because vendors
> appreciate the FCC's attempts to be forward thinking and partly because the
> has issued the NPRM (comments recently closed) that suggests amendments to
> these rules (like allowing more power in areas where the noise floor is
> below certain thresholds or more power when sectorization is used). This
> NPRM is in part a direct result of their own internal discomfort with their
> own granted exceptions (Navini was also given one).
>
> I hope this helps you to understand this seeming dichotmy.
>
> Regards,
>
> Patrick Leary
> Alvarion
>
> -----Original Message-----
> From: Ivan Bojer [mailto:[EMAIL PROTECTED]
> Sent: Friday, January 30, 2004 11:21 AM
> To: Wireless
> Subject: [BAWUG] Vivato and FCC part 15
>
>
> Can anyone explain how is this device FCC compliant
> and at the same time has 25W (44dBm) of EIRP (look at the spec)?!
> I though 36dBm is the max ?!
>
> http://www.vivato.net/download/SwitchDataSheetFinalV4.pdf
>
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