[STDS-802-16] [LE] TV bands - problems and solutions
to: 802-18-SG1
cc: [LE] stds-802-16
Dear Carl, John, Victor, All,
Here are the results of my short research regarding the
usage of TV bands for BWA, to be considered in the 802.18
response to FCC:
BASE STATION
-can comply with Part 15.209 requirements (OOB emissions
at levels of -50...-55dBm eirp), only if RF filters are used;
- TV Interference (for Analog TV, 1.2MW average transmission
power, based on FCC data base) to BWA BS, using John's
propagation model (LOS with slope of 3.6 instead of 2), 600MHz:
- 3 dB RSL (receive sensitivity level) degradation, for QPSK
1/2, first adjacent channel, at distance of 100km; higher
degradations at shorter distances;
- 3 dB RSL degradation, second adjacent channel: 15km.
This result shows that from BWA p.o.v., the system should
operate at >15km from the TV transmitter, if using the
SECOND adjacent channel. No receive BS filters were
considered in this computation.
- The interference to TV receivers can be mitigated if the BS is
mounted on high pools,etc. Here comes the role of professional
installers.
- BS filters can be prepared, if FCC, based on the GPS BS
positioning and a data base, will announce with, say 1 month
before, the channel, power and position of a new TV transmitter.
FWA SUBSCRIBER TERMINAL
- for 30dBm eirp Tx power, does not comply with Part 15.209
requirement of -50-55dBm eirp; a realistic target will be
65-70dBc, but 80-85dBc is too far from there;
- FWA SS to TV interference is anyway too high, even at
15.209 levels.
In conclusion (to be included in the relevant chapters of 802.18
response):
- a guard band is needed between a TV occupied channel and
a BS transmission; this guard band is necessary to achieve
compliance with Part 15.209 requirements;
INSERT in 15.244 (d): . Radiated emissions that fall outside the
TV broadcast channel(s) where the device operates, including
guard bands, etc.
- professional installers are needed for BS installation, to
minimize the interference to nearby TV receivers, due to OOB
signals;
- GPS and automatic management are necessary to announce
a change in channel usage in a given area
- a dedicated frequency band is necessary for BWA transmitters;
for example, by assigning one or two pools of higher channels
for this (requested new ruling); the filter+switch cost is aprox.
USD 1; INTRODUCE new paragraph, with a proposed solution
- the 15.209 levels may be achieved only using RF filters for that
band;
- professional installers are needed to install roof-top FWA.
KR,
Mariana
Marianna Goldhammer
Director - Strategic Technologies
Alvarion, Ltd.
10 years of wireless expertise
21 HaBarzel Street
P.O.Box 13139, Tel Aviv 61131, Israel
Tel: (972)- 3 -6456241/6262
Fax: (972) -3 -6456204
Mobile: +972 544- 22 55 48
Email: marianna.goldhammer@alvarion.com
www.alvarion.com
This mail was sent via mail.alvarion.com
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