Energy consumption of telecommunication access networks

Figure 9: Example of the obtained information on HFC network areas. Unlike the DSL access technology, HFC networks do not suffer from length restrictions. In this context, the spatial location of the fibre nodes and the CMTS becomes less important because the maximum cable length is smaller than the allowed one. Far more important than the cable length is the service group size. It describes howmany subscribers are fed from a single fibre node. All subscribers in a single service group share the available data rate so that the service group size determines the minimum data rate for each subscriber. Hence, a green field approach by varying the service group size is chosen. Similar to the HFC networks, FTTH networks do not suffer from length restrictions. The FTTH – GPON technology has a characteristic which is similar to the HFC service group size: the splitting factor. The splitting factor also determines the minimum data rate for each subscriber. GPON is therefore also a shared medium. Contrary to the HFC networks, a FTTH – Point-to-Point network is not a shared medium technology. Hence, there is no service group size or splitting factor. The limiting factor is however, howmany cable lines can be structurally combined in a single Point of Presence. Because of these characteristics, a green field approach with a maximum PoP size is chosen. 14