The communication method "PLC" that was not popular in ordinary households, the reason why it is attracting attention again

HD PLC for communication by connecting a modem to an existing outlet

How is HD PLC different from other communication methods?

Wired LANs and wireless LANs (and PLCs, of course) each have their advantages and disadvantages. Wired LAN is attractive for its high-speed communication speed, but on the other hand, it is necessary to install a LAN cable inside the wall. If you increase the number of rooms that use a wired LAN, wiring work will be required each time. On the other hand, wireless LAN does not require wiring and is easy to install, but it has the property that radio waves tend to weaken (communication speed drops) if there are obstacles such as walls and ceilings.

The advantage of HD PLC is that you can communicate in any room with an outlet just by plugging in the modem. Since it is a wired communication, there is no problem of communication failure due to obstacles. Another advantage is that the communication distance is long. A major feature is that you can earn a communication distance of 2km or more by using a mechanism called multi-hop.

The disadvantage of HD PLC that uses the high frequency band is that it tends to be a source of interference such as wireless. For this reason, PLCs have various regulations, and high-speed PLCs are basically used in closed networks such as home networks, buildings, and factories.

The biggest reason why HD PLC has not become popular for general residential use is its slow communication speed. While both wired LAN and wireless LAN currently support communication speeds of several Gbps, HD PLC has a maximum communication speed of 30 Mbps and an effective value of about 20 Mbps. The amount of data in Internet communication is increasing year by year, and the amount of data in the content itself such as photos and videos has also increased, so this communication speed is difficult.

Against this background, the use of HD PLC for residential use has gradually declined and is now almost non-existent. However, looking at the industrial field, there are many situations that do not require that much communication data, so there are many scenes where it is easy to take advantage of HD PLC.

HD PLC is attracting particular attention in the industrial IoT field. With the gradual decrease in the working population, IoT is progressing in industrial fields such as factories and farms. In many industrial fields, the amount of data used by IoT is not that large, so the communication speed of HD PLC is sufficient.

In addition, the Radio Law, which was deregulated at the end of June 2021, made HD PLC possible for three-phase, three-wire power lines mainly used in factories. It can now be used on previously unrecognized steel vessels, expanding the range of HD PLC usage.

When is HD PLC actually used?

Panasonic is one company that has been focusing on PLC from the beginning. Today, Panasonic Life Solutions has already introduced HD PLC in various industrial fields. An easy-to-understand introduction example is an existing facility. For example, if you try to convert an operating factory to IoT with a wired LAN, the construction cost will increase. With HD PLC, you can use existing outlets and power lines, which can significantly reduce installation costs.

With the above-mentioned multi-hop technology, it can be installed without a hub even at sites that require a hub every 100 m in the conventional construction method. Even if it is installed in a place where radio waves do not reach, such as in a long tunnel, or where the construction cost is high if a wired LAN is laid, there is a big cost advantage.

As an example where the merits are easier to understand, Panasonic introduced the student dormitory of Nagoya University. At Nagoya University, remote lessons are increasing due to the Korona-ka, but until now, VDSL over telephone lines had been adopted, so there was the problem that the load on the network was too high.

Therefore, we introduced HD PLC based on the requests of students and realized problem solving with a sense of speed. With the introduction of wired LAN, it takes about 3 months to bid, about 1 month to construct, and about 2 weeks to construct the optical cable, whereas with HD PLC, wiring work is not required. In addition, LTE and 5G Wi-Fi routers can be considered as communication methods that do not require construction, but this incurs a running cost of around 2,000 yen per room per month.

However, when installing HD PLC in an apartment building, the problem is the communication speed. In the case of Nagoya University / Student Dormitory, PLC adapters are installed in 137 units, but if the effective value of about 20 Mbps is divided among all the units, the low-speed communication will be at a level that cannot be used for online classes. Therefore, the communication speed is secured by limiting the number of units to which communication is allocated with a filter.

HD PLC is a communication method that has some problems, but as the deregulation was eased by the revision of the law in June 2021, there is a possibility that the number of situations that can be applied will continue to increase along with the development of the law. Currently, it is often used in a limited environment, but in the future, it may be used more often in familiar places.