Page 51 - GuideFWA

This is due to the slot antenna effect of the small gaps between pannels. One propagation model
(ETR 310, page 45) for semi-high soft partitions, but without interior walls, is:

L = 41 + 20 log s + G × max [0, (s - 10)] dB

where G is 0.37 dB/m or 0.59 dB/m, depending on the density of the partitions.

Another alternative is to use complex computer modeling software tools that are readily available
on the market, where exact models for real building layouts, floor by floor, can be modeled using
ray-tracing techniques. If time had permitted, several examples of real building interior
propagation and losses could have been submitted. These modeling software tools could also be
used for real urban area simulations.

4.6.2.31 Noise Floor Rise vs. Separation

The noise floor increase versus distance between the interfering transmitter and victim receiver is
considered to be more useful in a practical sense than simply knowing what distance is required
to achieve a 1-dB rise in the noise floor. In the practical application of the table, a system
provider trying to set up a site knows that there are potential interferers some distances away.
Most of the time, the provider does note have control over how far away the interferer will be,
and needs to know how much the noise floor will be increased by the interferer, to design the
system to work in the presence of the interference. Although the summary table shows only the
separation distance required for a 1-dB rise in the noise floor, the noise floor increase vs. distance
is more useful for a system operator and is shown in the detailed results for each case.

4.6.2.32 Spurious, out of band, unwanted emissions vs. modulation mask

In this study, only one interference component, i.e. emission due to modulation, is considered for
some technologies (e.g. FWA), while spurious emission is considered in other technologies (e.g.
IS-95). For better estimate the interference scenario, all the unwanted emission should be
considered.

4.6.2.33 Space for guard-bands

The PHS FWA recommendation recognize the need for guard-bands at the 1910 and 1930 MHz
band edge. A similar recommendation for DECT FWA systems was not accepted by DECT
experts. However, in cases where low traffic is anticipated DECT channels 1 and 10 could be
turned off to reduce the probability of interference from licensed PCS.

4.6.2.34 Antenna sectorisation, traffic

In general it is necessary to fully account for the interaction between antenna sectorisation and
choices, cell sizes and traffic capacities. There is some doubt expressed here since the analysis
presented earlier has not properly reflected this need.

Inter-American Telecommunication Commission 37