Integrated Wireless-pon access Network Architectures Milos Milosavljevic

Figure 3-9: A simple point-to-point link for demonstrating fibre chromatic dispersion effects 
Table 3-1: Photo-diode parameters in VPI 
Parameter 
Value 
Unit 
Responsivity 
1 
A/W 
Photo Diode Model
PIN 
/ 
Dark Current 
0 
nA 
Thermal Noise 
0 
pA/(Hz)^
1/2 
Shot Noise 
OFF 
/ 
For transmission, a 20km SSMF reel has been utilised with standard parameters as shown in 
Table 3-2.
Table 3-2: Fibre parameters
Parameter 
Value 
Unit 
Length 
20 
km 
Group Refractive Index 
1.47 
/ 
Attenuation 
0.2 
dB/km 
Dispersion 
16e-6 
s/m^2 
Dispersion Slope 
0.08e3 
s/m^3
The obtained transfer function in Figure 3-10, measured at the output of the photodiode, 
demonstrates amplitude variations at certain frequencies caused mainly due to the fibre 
chromatic dispersion. Based on these primary results it becomes evident that the application of 
RoF needs to be carefully designed in order to avoid high attenuations at certain subcarrier 

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Chapter 3
frequencies. The number of subcarriers in the network could thus be limited not only by the 
small bandwidth of optical and electrical components but also by the fibre chromatic dispersion. 
Figure 3-
3.4.2 OFDM Transmission Evaluation 
Having previously established the key characteristics of RoF
important to evaluate the impact of optical fibre
modulation is utilised in all emerging broadband wireless standards 
performance evaluation in view of its compatibility with optical 
architectures enabling wireless/optical integration is paramount
OFDM, error vector magnitude (
transmitter ability to produce