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5-19
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CONFIDENTIAL
Estimating RF Coverage
5.4.3
Examples of Design Estimates
Example Design Estimate for an 850 MHz TDMA Application
1.
Wireless service provider’s requirements
:
• Cellular (859 MHz = average of the lowest uplink and the highest downlink
frequency in 850 MHz Cellular band)
• TDMA provider
• 12 TDMA carriers in the system
• –85 dBm design goal and 95% area coverage
• Base station with simplex RF connections
2.
Power Per Carrier
: The tables in Section 5.2, “Maximum Output Power per Car-
rier,” on page 5-4 provide maximum power per carrier information. The 800 MHz
TDMA table (on page 5-5) indicates that Fusion SingleStar can support 12 carri-
ers with a recommended maximum power per carrier of +7.5 dBm. The input
power should be set to the desired output power minus the system gain.
3.
Link Budget
: In this example, a design goal of –85 dBm is used. Suppose 3 dBi
omni-directional antennas are used in the design. Then, the maximum RF propa-
gation loss should be no more than 95.5 dB (+7.5 dBm + 3 dBi + 85 dBm) over
Table 5-16
Approximate Radiated Distance from Antenna
for 1900 MHz PCS Applications
Facility
Distance from Antenna
Meters
Feet
Open Environment
72
236
Moderately Open Environment
56
183
Mildly Dense Environment
49
160
Moderately Dense Environment
40
132
Dense Environment
29
96
Table 5-17
Approximate Radiated Distance from Antenna
for 2.1 GHz UMTS Applications
Facility
Distance from Antenna
Meters
Feet
Open Environment
69
226
Moderately Open Environment
54
176
Mildly Dense Environment
47
154
Moderately Dense Environment
39
128
Dense Environment
28
93
