Integrated Wireless-pon access Network Architectures Milos Milosavljevic

Chapter 8 Project Achievements and Future Work 
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8.3 Future Work
 
This section summarises the key network features that could be further investigated, either 
through an independent research programme or through a FP7 consortium [21]. According to 
research initiatives the next generation network consolidation is seen as general trend for future 
OPEX and CAPEX optimization [1]. Extending the reach of the access segment will possibly 
facilitate simpler network structures, with fewer metro and core COs collecting the traffic 
from/to wide network areas. This consolidation will enable optimum use of network resources 
(shared by a large numbers of users), a relevant reduction on operation and maintenance costs 
and important real-state savings. Extended reach capabilities are crucial also for scenarios such 
as rural deployments that would not be feasible, either in a technical or economical way, using 
currently available technologies. Therefore, the scalability of the architecture should be further 
explored by investigating its ability to demonstrate a long reach converged optical/wireless 
network with low deployment cost.
However, the long fibre links, in the range of 100 km, could result in high latencies for radio 
signals and high power adjacent channel interference. Latency is typically introduced since the 
exchange of communication concerning the wireless channel management and control is 
delayed resulting, for example, in decreased spectral efficiency across a cell. This could be 
resolved by the introduction of an intermediate node, middle office (MO), between the CO and 
a remote base station where all the base station functionalities could be located. The MO will be 
also responsible for generation and transmission of RoF carriers over 20 km of fibre only, as has 
been demonstrated in Figure 8-1 below. The enhanced Node Bs (eNBs) are the typical base 
stations encountered in the next generation LTE deployments performing signal generation, 
detection and scheduling. The notation P1 in Figure 8-1 represents that signal processing is split 
between remote base station and MO.

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