Page 612 - 5G Basics - Core Network Aspects

2 Transport aspects

8.4 Possible RoF over ODN configurations and characteristics

There can be several types of configurations as a function of the use of optical wavelength or power passive
devices.
The wavelength based ODN is described in Figures 8-2-a and 8-2-b and comprises an optical head end,
connecting to the ODN through one- or two-fibre links. The optical head end houses a set of optical
transmitters and receivers based on dense wavelength division multiplexing (DWDM) or coarse wavelength
division multiplexing (CWDM). The DWDM and CWDM characteristics have also to be considered for the
passive wavelength multiplexer (WM). Two fibre ODN could be considered for CWDM and DWDM in
absence of wavelength diplex definition. One fibre and DWDM colourless transceiver is considered as the
target solution for the ONU and OLT.
Figures 8-2-a and 8-2-b present two examples of configuration authorizing a link between a base band pool
and one or several antenna sites with high number of RoF signals (NRT × NRFB × NRS ×NMIMO) based only
on the use of wavelength division multiplexing. These ODN scenarios could be typical use cases for macro
and micro cell applications.

Figures 8-2-c and 8-2-d present two examples of configuration with optical power splitter and wavelength
MUX and DEMUX based ODN. The optical splitter allows time division multiplexing (TDM) and time
wavelength division multiplexing (TWDM) techniques to be used for RoF application. The WM also allows
WDM technics to be used for RoF applications in coexistence with TDM and TWDM interfaces. One-fibre
ODN is only considered in these scenarios based on diplex technology. We could consider that the use of
the existing ODN splitter reduces the number of potential number of RoF ONUs available (cf. ODN end
faces, wavelength spectrum allocation) and so one or several antenna sites with a limited number of RoF
signals in comparison with the two previous scenarios could be used. These ODN scenarios could be typical
use cases for micro and small cell applications.

Concerning Figure 8-2-c for Digital RoF, TDM or TWDM PON interface should require adaption of the PON
interfaces (e.g., fixed bandwidth allocation algorithm) to allow a transmission of a continuous traffic with
controlled latency and jitter.

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