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[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


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