Page 230 - GuideFWA

spectrum-sharing possibility would be to allow FWA systems to operate in the 1910-1930 MHz
band in rural areas only.

25

20

PWT coverage area 15
per cell (thousands 10

of square feet)

5

0 5 10 20 30 50 100 200 300

FWA traffic (Erlangs/km2)

Figure 5.9: PWT coverage are per cell vs. FWA traffic density

5.1.2.4 Conclusions and Recommendations

This paper has extended the analysis provided in the Lucent contribution to the Mexico City
PCC.III meeting in September 1997, and has addressed the comments on that contribution
offered by the members of the Interference Experts Group. It is clear from the results presented
here that unless the FWA traffic density is low (less than 10 E/km2), the impact of the FWA
interference on a UPCS system will be significant. Therefore, UPCS systems will be able to
coexist with FWA systems only in low-density environments, such as rural areas, without a
severe reduction in cell coverage area.

This conclusion suggests that to ensure successful operation of UPCS systems, FWA systems
should not be allowed to operate within 1910-1930 MHz except in low-density (rural) areas. For
urban areas, one of the other bands identified by CITEL should be used for FWA systems.

5.1.2.5 Annex: UPCS coverage calculations

The PWT system is assumed to require a carrier-to-noise ratio of 13 dB plus 12 dB multipath
fade margin, for a total local mean C/N of 25 dB. The thermal noise floor (not including the
receiver noise figure) is assumed to be -115 dBm. If N FWA is the increase in the noise floor in
dB due to the FWA system (shown in Fig. 5.8), then the noise floor, in dBm, seen by the PWT
system is N = -115 + N FWA .
The propagation model used here to calculate the path loss between the PWT base and handset
indoors is the “Ericsson” model (see ETR 310 [23], p. 43), given by:

216