Abstract
Integrated Wireless-PON Access Network Architectures
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Abstract
Next generation access networks should be able to cultivate the ongoing evolution in services
and applications. Advancements on that front are expected to exhibit the transformation of high
definition television (HDTV) and 2D services into ultra-HDTV and individual interactive 3D
services. Currently deployed passive optical networks (PONs) have been certified to be able to
deliver high quality video and internet services while in parallel broadband wireless standards
are increasing their spectral efficiency and subscriber utilisation. Exploiting the benefits of both
by providing an integrated infrastructure benefiting from the wireless
mobility and ease of
scalability and escalating bandwidth of next generation PONs are expected to offer service
providers the business models justifying the evolved services. In this direction, this thesis deals
with the means of transparent routing of standard worldwide interoperability
for microwave
access (WiMAX) signal formats over legacy PONs to and from wireless end users based on
radio over fibre (RoF). The concept of frequency division multiplexing (FDM) with RoF is used
for efficient addressing of individual base stations, bandwidth on-demand provisioning across a
cell/sector, simple remote radio heads and no interference with the baseband PON spectrum.
Network performance evaluation, initially through simulation, has displayed, in the presence of
optical non-linearites and
multi-path wireless channels, standard error vector magnitudes
(EVMs) at remote radio receivers and bit error rates (BERs) of 1E-4 for typical WiMAX rates
bidirectionally. To provide enhanced scalability and dynamicity, a newly applied scheme based
on extended wavelength
band overlay over the splitter, wireless-enabled PONs has been
progressively investigated. This allows for the routing of multiple
FDM windows to different
wavelengths resulting in significantly reduced optical and electrical component costs and no
dispersion compensation over the fibre. This has been implemented through the application of a
dense array wave guide grating (AWG) and tuneable filter in the optical line terminal (OLT)
and optical network unit/base stations (ONU/BSs) respectively. Although with the use of a
splitter the distribution point of the optical network
remains largely the same, vertical cavity
surface emitting laser (VCSEL) arrays provide colourless upstream transmission. In addition, an
overlapping cell concept is developed and adopted for increased wireless spectral efficiency and
resilience. Finally, an experimental test-bed using commercially available WiMAX transceivers
was produced, which enabled repetition of the simulation outcomes and therefore confirmed the
overall network performance.