Mạng lưới cấp điện áp thấp trên toàn thế giới có sẵn trong một số lượng rất lớn các hộ gia đình và có thể được sử dụng cho việc thực hiện của các mạng truy nhập PLC để khắc phục viễn thông được gọi là "dặm cuối". | PLC Network Characteristics 43 If the base station is not placed in the transformer unit the central point connection point to the backbone of the PLC network moves to another place in the network. However the position of the base station can move only along existing power supply grids Fig. . This can only cause varying distances between the base station and subscribers in various network realizations. Thus the topology of the PLC access network always remains the same keeping the same physical tree structure. Network Segmentation A PLC access network can be realized to include a whole low-voltage power supply network or to include only a part of a supply network. To reduce the number of users per PLC system and the network length it is possible to divide the low-voltage network into several parts . one PLC system per network section . In this case several PLC systems can work simultaneously in a low-voltage network. Fig. presents a possible segmentation of the low-voltage supply network that consists of three network sections. Each network section has a base station that connects a number of subscribers of a separated PLC access network. So there are three separate PLC access systems within the low-voltage network. In this way the number of subscribers who share the available network capacity is reduced. One result of the network segmentation in multiple PLC access systems is a reduced length of originated PLC networks operating in individual network sections. Accordingly the transmission can be realized with a lower signal power which is important because of the electromagnetic compatibility problem EMC Sec. Sec. . There are also a smaller number of potential subscribers in a network section than in the whole supply network and the transmission capacity is shared by a smaller number of PLC subscribers. The network segmentation is not limited only to network sections branches. Each part of a supply network could also be realized as a .