Broadband Powerline Communications Networks
Topology of an in-home PLC network
of the kind of in-home PLC network, it keeps the physical tree topology, such as PLC access
networks. Also, if the base station is moved to another place within the in-home PLC network
(e.g. to a wall socket), the physical tree structure remains. However, the in-home networks
are significantly shorter than the access networks, even if larger buildings are considered.
Some in-home PLC networks are organized in a decentralized manner, which leads to
a network structure without PLC base station. This is usually the case in the independent
in-home PLC networks, where the communication is organized by a negotiation between
all network stations. However, the physical tree network structure can be recognized in
those PLC networks, too.
3.1.4 Complex PLC Access Networks
In previous subsections, we have described network topologies of several PLC access
networks realized in various ways. We considered the position of the PLC base station
within a low-voltage supply network, network segmentation and interconnection, and PLC
networks with repeater and gateway technique, as well as the in-home PLC networks.
However, in a real environment, a PLC access network can be realized to include several
of these features, building so-called complex PLC network structures.
In Fig. 3.10, we present a possible PLC network configuration covering multiple low-
voltage networks and including different network elements. There are three supply net-
works in the example, each of them with a transformer unit supplying several branches,
which connect variable numbers of users (potential PLC subscribers), and having also
different user densities. The supply networks are interconnected (I) for the case in which
a transformer unit falls out ensuring permanent supply to all users. In the normal case, the
interconnection points are switched off, so there is no current flow between the supply
networks. On the other hand, the interconnection points can be equipped to allow the
transmission of high-frequency communications signals.
Because of the asymmetric division of the network users, there is a significantly higher
number of PLC subscribers in the second supply network (Fig. 3.10). Therefore, the supply