Page 254 - GuideFWA

considered in this study. We have to keep in mind that these assumptions are for simplification
purpose and may not be universal applicable for other cases and scenarios. For the DECT FWA
operating in frequency 1910 MHz - 1930 MHz [1], the DECT carrier frequencies at two band
edges are 1912.896 MHz and 1928.448 MHz, and the occupied bandwidth of each DECT
channel is 1.728 MHz.

Assuming the FWA transmitters are uniformly distributed over the service area, the probability
density function(pdf) of the separate distance between the j-th FWA transmitter and the PCS BS
receiver can be approximated by [16]

Pr(d j ) = 2d j , r=dj =R (17.6)
R2 - r2

The total interference power received by the PCS BS receiver from FWA is the sum of each
individual FWA transmission Ij (in linear scale) from equation (17.5).

One of the indexes that is commonly used [1, 26, 27] in assessing the receiver performance
degradation from external noise is the rise in noise floor. The rise in the affected receiver noise
floor is defined as the ratio of the affected receiver noise floor plus the received external
interference power to the noise floor. The noise floor includes thermal noise floor, noise figure
and internal (self) interference. The index provides a good indication showing how much the
receiver performance is suffered due to the increase of the external interference. The larger of
the value the more performance degradation the system experiences.

The equations in determining the affective receiver noise floor for PCS IS-95 BS and PCS IS-136
BS are provided in [26]

N CDMAB = N TWCDMA FCDMAB M I (17.7)
and

N TDMAB = N TWTDMA FTDMAB (17.8)

where NT (-174 dBm/Hz) = thermal noise density,
FCDMAB (6.2 dB [1] ) = CDMA base noise figure referenced to the antenna connector,
M I (3.8 dB corresponding to typical 58.3% loading ) = receiver interference margin, a
rise in the noise floor due to the interference from other CDMA users,
FTDMAB (6.2 dB) = TDMA base noise figure referenced to the antenna connector,
WCDMA (1.23 MHz) = IS-95 CDMA bandwidth,
WTDMA (30 kHz) = IS-136 TDMA bandwidth.

The noise floor for CDMA and TDMA based on equation (17.8) are -103 dBm and -123 dBm,
respectively. Using Equations (17.5) through (17.8), the rise in the base station noise floor can

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