Integrated Wireless-pon access Network Architectures Milos Milosavljevic

Chapter 8 Project Achievements and Future Work 
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in the FDM window would be increased, to address larger number of ONU/BSs. As a result, 
increased network penetration could require sophisticated, high bandwidth optical and electrical 
components. 
To overcome the above issues, an enhancement solution of the access network architecture was 
developed, both in software and hardware integrating the standard wireless signal formats over 
a multi-wavelength splitter-PON, again based on RoF. FDM was still applied to address 
individual base stations sharing each of the utilised wavelengths. Apart from different 
wavelengths transmitting different FDM windows, the proposed system also allows for a given 
FDM window to be propagated on multiple wavelengths. This relaxes significantly the 
bandwidth requirements of optical and electrical devices while enhancing the network 
scalability. This extended wavelength band overlay scheme overcomes the need for complex 
dispersion compensation techniques as it avoids the use of high frequency subcarriers in each 
FDM window.
The overall network performance has been initially evaluated by means of a powerful simulator 
incorporating extensive functionalities of RF transceivers and wireless propagation media as 
well as the complete building blocks of PONs including propagation degradation and end-to-
end power budgeting engineering. The compliance of the developed simulator to the individual 
wireless and optical specifications has been established by the demonstration of an experimental 
set-up and the direct comparison of the obtained performance figures. For WiMAX routing over 
xPON architectures, inclusive OFDM transmitters and receivers are devised in VPI in co-
simulation with MATLAB, utilising all necessary functional blocks. The latter include symbol 
mapping, a 256 point IFFT, 1/4 cyclic prefix and DAC conversion with 14-level quantisation. 
Square root-raised-cosine filters with 25% roll of were also used for I and Q ISI minimisation 
prior to RF up-conversion. The bandwidth of these filters is equivalent to the OFDM symbol 

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