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overlapping factor is about 30%, it means that 30% of EACH cell at its border is overlapped by
other cells.

Then, as the external interference effect is applied to a limited number of cells or sectors, it is
very likely that if one cell (i.e. one base station) or sector is affected by an external interference,
its adjacent cells or sectors are not.

Thus, since the overlapping factor is always higher than any of the cell coverage reduction given
in above table, the service continuity along the whole coverage area can be still assured within a
range of desensitization between 0.5 and 3 dB. Obviously, for higher values of desensitization
(e.g. higher than 2 dB), the situation could be more critical since the cell reduction factor is
closer to the overlapping area (even higher than the minimum overlapping area of 17%).

The conclusion is that THE IMPACT OF A RISE IN THE NOISE FLOOR BETWEEN 0.5 AND
3 dB OVER THE VICTIM SYSTEM IS NOT CRITICAL, that is a reason why in report [1] a
range from 0.5 to 3 dB was considered, and within this range the reference value was chosen
equal to 1 dB in order to select a very pessimistic value (worst case analysis approach).

The above analysis shows that selected criteria of 0.5 to 3 dB rise in the noise floor is a relevant
choice for a comparative analysis [1]. That this criteria also represents a very pessimistic worst
case scenario in absolute terms for a real deployment, is further demonstrated by the analysis in
[21], where as low as 100m separation between FWA base and PCS base have almost no
influence on the PCS system traffic.

5. UPCS AND FWA ISSUES

5.1. LMNQ VIEW

This subsection contains two studies of the effect of co-channel interference to UPCS from FWA
systems both applications were to share the use of the 1910-1930 MHz band. The first study was
submitted to the PCC.III meeting in Mexico [17] and the second is a response [16] to comments
received at the meeting in Mexico. These studies show that there is a significant deterioration of
UPCS service cause be FWA systems and recommends that the two types of applications be
allocated difference frequency bands of operation to prevent interference to UPCS systems.

5.1.1. Analysis of Cochannel Interference from DECT FWA Systems to Isochronous UPCS [17]

5.1.1.1 Introduction and abstract

PCC.III is studying the feasibility of operating fixed wireless access (FWA) systems and
unlicensed personal communications systems (UPCS) in the 1910-1930 MHz band
simultaneously in the same geographic area.

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