Integrated Wireless-pon access Network Architectures Milos Milosavljevic

Chapter 3 Optical and Wireless PHY Integration
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router at customer premises [16]. The wireless architecture is based on a mesh topology for 
bidirectional transmission from the OLT to end users via multiple hops. The end terminal 
mobility can be supported at the IP layer by one of the three dominant approaches developed at 
the Internet Engineering Task Force (IETF), namely, mobile IP, migrate, and host-identity 
protocol [16].
Another integrated optical/WMN architecture following a similar approach to WOBAN is the 
“grid reconfigurable optical and wireless network” (GROW-Net) [17], which also attempts to 
exploit the cost-effectiveness of wireless mesh networks in urban areas. The initial intention of 
this project was to define loop-based optical routing strategies for the optical part combined 
with routing strategies defined for the wireless to potentially exchange some information that 
will affect the decisions of both networks. However, further evolutions of the architecture 
eventually led to solutions that are similar to WOBAN based on an optical ring serving as the 
backbone infrastructure, gathering traffic from the wireless multi-hop network and forwarding it 
to the central office. The central office is in control of network operation and management.
In view of the mesh topologies utilised, packets in both these schemes need to traverse many 
nodes before they reach their destination. This would most certainly impose additional delays 
therefore requiring complex MAC layer designs, applicable to both wired and wireless, parts of 
the network, in order to compensate for the multiple hops. Also, the network performance 
largely depends on placement of ONUs in the field [16].
Finally, for the implementation of RoF solutions developments, in terms of bandwidth and 
carrier frequency of optical components, particularly relevant to generating light and optical 
modulation, are of special interest. An example of that would be the advances in vertical cavity 
surface emitting lasers (VCSELs) due to their low bias currents suitable for high bandwidth 
modulation and operation at longer wavelengths [18, 19]. Recently, low-cost VCSEL arrays 

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