Page 255 - GuideFWA

Prob{I < x}be expressed as a function of the user call density as well as geographic and frequency
separations between the interfering sources and victim receiver.

17.1.3. Simulation Results

The first case is to study the interference impacts of the DECT FWA system to IS-136 PCS
receiver with various maximum receivable distance, R. In real implementations, R could be
varied by several factors like receiver sensitivity, interferer’s output power, antenna design and
channel conditions, etc. The parameters used to be applied to the simulations are shown in Table
17.1 and the following:
IS-136 PCS receiver[1]:

• PCS Rx band: 1930-1945 MHz

• FWA Tx Band: 1910-1930 MHz

• NE: 120 Channels
• antenna gain: 15 dBi

• antenna height: 25 m

• minimum receivable range, r: 20 m

1
0.9
0.8
0.7
0.6
0.5
0.4 R = 1 km
0.3 R = 5 km
0.2 R = 10 km
0.1 R = 15 km

0

Interference, dBm

Figure 17.2 Interference CDF for business area

Simulations with different base station maximum receivable distance R ranged from 1 km to 15
km in the business area are performed. The cumulative distribution functions (CDF) of the
interference are shown in Figure 17.2.

From Figure 17.2 we note that the interference level rises as the maximum receivable distance R
increases, and gradually flatten out when R reaches to a relatively large value. This makes sense
because the number of the transmissions ‘seen’ by the PCS receiver increases when R becomes
larger. When the maximum receivable distance extends to a large range the additional
interference sources located in far side become less significant such that they have very little
-120
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-106

-99
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-85
-78
-71
-64
-57
-50
-43
-36
-29
-22

Inter-American Telecommunication Commission 241