# Analysis of Video Transmission Capabilities in a Simulated OFDM-Based Supplementary BPL-PLC System
## 1 Introduction  
The broadband over power line-power line communication (BPL-PLC) technology offers broadband transmission by reusing power lines for data communication at high speeds, usually up to around 200 Mb/s within the 2 to 30 MHz frequency range. BPL includes all technologies over power lines, particularly those for carrying broadband signals for computer networks and/or smart grid (SG) utilities. At the beginning, BPL was designed for billing data acquisition from electricity meters (mainly at low voltage). However, one can find numerous examples in the literature of its effective application to control intelligent devices, including the Internet of things (IoT) concept, and/or to transmit various data [1, 2, 3]. BPL technology enables, among others, broadband Internet access via electrical sockets at home. It operates at speeds close to that of a digital subscriber line (DSL). Since BPL reuses the existing grid infrastructure [4, 5, 6, 7], it can be used wherever DSL communication is not available. Nowadays, its utilization in medium-voltage industrial networks seems to be of particular interest, especially in smart grids and the Industry 4.0 concept. The authors' experience also shows that there is a real chance of using the BPL technology in an existing mediumvoltage (MV) mine power grid infrastructure as an additional transmission medium, including various signals, e.g., audio and video [8; 9; 10; 11; 12], whenever an emergency situation occurs. This would surely contribute to a significant increase in work safety in the oil and mining industry. The main advantages of the BPL technology are as follows [13; 14]:  
* Low cost of implementation, comparable to the narrowband PLC technology;
* High transmission speeds;
* Easy installation. Furthermore, there is a possibility of extending the TPC/IP backbone network to medium voltage/low voltage (MV/LV) stations, as well as the coexistence of many other systems, not only smart metering (SM) or smart grid, including:  
* Power grid supervision system;
* Control of street lighting and traffic lights;
* Access systems control and monitoring, etc. However, it should be noted that despite a number of advantages, BPL technology is not resistant to various types of electromagnetic compatibility (EMC) disturbances (both induced and conducted). As a result, a decrease in the efficiency of this technology can be observed. Data transmission speed decreases, whereas errors increase [15; 16]. It must be added that the BPL is not welcomed by amateur broadcasters and other users due to noise production. BPL becomes a source of radio waves and causes interference with other technologies. Power grids are not intended, and therefore also designed and constructed to transmit high-frequency signals. For the complex topology of electricity network, the BPL channel presents frequency selection, multi-path effects, high susceptibility and high attenuation. Owing to the good characteristics of anti-multi-path fading, orthogonal frequency division multiplexing (OFDM) [17] is often adopted as a preferable modulation technique in BPL. As for the possibility of using BPL technology in medium voltage (MV) lines, it must be noted that it is an alternative to much more expensive fiber-optic systems (lower costs, greater ease, and higher speed of implementation). In many cases it is the only option, e.g., in highly urbanized areas. In low voltage applications, the BPL modems are connected directly to 230/400 V networks. However, in case of MV applications, modems must be joined via appropriate couplers, either capacitive (Figure 1a) or inductive (Figure 1b). They isolate from high voltage and allow safe transmission of the high-frequency signal over the power line. The distances over which data can be transmitted via medium voltage lines using BPL technology range from several hundreds of meters to about 1.5 km.