Note this number can be either decreased or increased based on the
system under consideration and measured/simulated results. Also shown is that each interferer is
independently faded.
3.5.2 Adjacent Channel Interference
ACI arises from other signals that transmit on an adjacent frequency channel at the same time the
desired signal is transmitting. In both TDMAand CDMAsystems the spectrum available to the service
provider will be segmented. This means that adjacent channels can be of either similar radio access
technology or a different one. Moreover, depending on the choice of the radio access technology,
modulation scheme, and emissions mask, channels beyond adjacent can contribute to this form of
unwanted interference, let us provide a picture given in Fig. 3.43.
Below we see an alternative ACI can potentially create enough in-band interference in the desired
signal, thus causing performance degradation. Asimplified model of ACI is considering a single side
of the transmitted signal and is given below (see Fig. 3.44).
WIRELESS MULTIPATH CHANNEL 149
FIGURE 3.43 Transmit spectra for adjacent and alternate adjacent channel interference.
FIGURE 3.42 Simplified CCI simulation model.
fN fN+1 fN+2 fN??“1 fN??“2
Hz
Desired
fN = Channel Number Adjacent Alternate
Adjacent
Modulator
Signals
#j
UE
Rx
j th
Cell
Modulator
#j+6
n(t)
Rj(t)
Rj+6(t)
( j+6)th
Cell
.
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