Smart Home Core Technology "Power Line Carrier Communication Technology"

With the development of new technologies such as the Internet of Things and cloud computing, the early wired technologies used in smart homes have the characteristics of strong data transmission reliability and high transmission rate. However, due to their large size, poor flexibility, and the need for drilling holes in the wiring, the construction is complicated. , fixed function, relatively high cost, in the smart home application began to seem powerless, replaced by wireless communication / network technology. Wireless communication/network technology has features such as flexibility, good mobility, and strong scalability. It is more in line with the needs of home network communications. It has become a trend in the development of smart home technologies and will greatly promote the development of smart homes and make the home life more accessible. Intelligent.

The smart home integrates and systemizes home appliances such as doors and windows, lighting, home appliances, security, and audio and video, and requires certain devices to be connected together for unified control and management. Wireless communication/network technology greatly meets this demand. . With the continuous improvement of home control and intelligence, wireless communication/network technology has also been continuously improved and improved.

Smart Home Core Technology - Power Line Carrier Communication Technology

In 2008, Hurricane Ike swept through southeastern Texas, and the entire North Houston metropolitan area was lined with power from the north wind. Just as the firefighters put out fighting and fire fighting, the staff members wear rubber boots, wear raincoats, and hold flashlights. They rush through the streets and search for wires that are blown by the north wind. At that time, 2 million families waited anxiously in the dark. In some areas, this type of search needs several weeks, and the total loss caused by power outages is up to several billion dollars.

At the other end of the globe, Stockholm is experiencing a major traffic jam during peak hours. Several bridges connecting the capital city of Sweden have become a bottleneck in traffic and vehicles have become congested. The discharged exhaust gas pollutes the air. Millions of gallons (us gallums, lus gol≈3.79L) of fuel are wasting and pedestrian safety is also threatened.

Using the terminology of the information technology industry, the above conditions are all “dumb network problems”, indicating that people do not really understand the commuter traffic or the intrinsic role of currents. On the basis of the original, "let the broken wires go to the maintenance workers themselves and let the roads themselves tell the vehicles where to go" in order to achieve intelligent operation and application, and the power carrier technology is a model among them.

Power line carrier communication technology features

At present, products in smart homes are communicated through optical fibers, cables, etc., and the cost is relatively high. Therefore, the construction of smart homes for a family needs 5,160,000 yuan. Therefore, it is difficult to popularize in the average family. After adopting the power line carrier communication method, only the carrier chip needs to be added to various electric appliances, and the power line carrier communication method is added to the gateway without rewiring, so the cost can be greatly reduced. Under the condition that the cost is greatly reduced, power line carrier communication chips may become the standard configuration of home appliances in the future.

Power Line Communication (PLC) utilizes high-voltage power lines (usually referred to as 35 kV and above in the power carrier field), medium-voltage power lines (referring to lOkV voltage levels) or low-voltage distribution lines (380V/220V lines) as Information transmission media A special communication method for voice or data transmission. The greatest advantage of this technology is that it relies on the power line network and does not require re-wiring. It has the characteristics of low construction and operating costs.

Because there is no need to re-establish the network, as long as there is a wire can carry out data transmission, so PLC has become one of the best solutions to solve the problem of smart home data transmission. At the same time, because the data is only transmitted in the home range, the troubles that hamper PLC applications will be greatly reduced. Even the remote control of home appliances can be realized by the traditional network first connected to the PC and then controlling the home appliances. The cost of the PLC modem module is much lower than that of the wireless module.

At present, the application of PLC mainly focuses on family intelligence, intelligentization of public facilities (such as remote meter reading systems, remote monitoring systems for street lamps, etc.) and industrial intelligence (such as data collection of various types of equipment). Technically, power line carrier communication is no longer a category of point-to-point communication, but highlights the concept of open network architecture. This allows each control node (controlled device) to form a network for centralized control. Currently, it has a power line carrier application. There are not many enterprises with network protocols and network concepts. There are Echelon's LonWorks network abroad, KaiStar Electronics' power line carrier remote intelligent control system and Raisecom's Ruisconda intelligent control network. Its network protocols are based on the international standard protocols EIA 709.1 and EIA 709.2.

Development of Power Line Carrier Communication Technology

The history of transmitting information via power line carrier communication can be traced back to the 1920s. In the 1950s, low-frequency high-voltage power line communication technology has been widely used in monitoring, remote indication, equipment protection, and voice transmission. From the late 1950s to the early 90s of the 20th century, power line carrier communication began to be applied to medium-voltage and low-voltage power networks. Its development work focused on power line automatic meter reading, grid load control, and power supply management. In the late 1990s to the present, power line carrier communications began to be used in Internet applications.

Development of Power Line Carrier Technology

The history of transmitting information via power line carrier communication can be traced back to the 1920s. In the 1950s, low-frequency high-voltage power line communication technology has been widely used in monitoring, remote indication, equipment protection, and voice transmission. From the late 1950s to the early 90s of the 20th century, power line carrier communication began to be applied to medium-voltage and low-voltage power networks. Its development work focused on power line automatic meter reading, grid load control, and power supply management. In the late 1990s to the present, power line carrier communications began to be used in Internet applications.

Development of Power Line Carrier Technology

Although with the development of the time, technical problems can be solved and overcome in the end, but from the current situation of domestic broadband network construction, the time and space reserved for the PLC is not enough. According to the "China Power Carrier Communication Industry Market Demand and Investment Forecast Analysis Forecast Report Preview," major operators have launched a large number of broadband access services such as ADSL, optical fiber, and wireless networks since 2000, leaving the power line Internet access for living space. Has been constantly compressed by other access methods.

"Power cat" is the latest application and development of power line carrier technology. The so-called power cat, or "power network bridge", is a device that modulates network signals onto wires and uses existing wires to solve network cabling problems. As the third-generation network transmission equipment that science and technology has spawned, “Power Cat” is now swept the world with its unique advantages. Its working principle is to use wires to transmit high-frequency signals, load high-frequency signals carrying information into current, and then use power transmission. The power network bridge that receives the information decomposes the high-frequency signal out of the electric current, thus realizes various applications such as surfing the net, making a telephone call, watching 1PTV, network camera, storage server, game machine, etc. on the basis that does not need to rewire. To sum up in a simple sentence is a "wire is the network line, easy access to the Internet is not limited."

From the perspective of the market application structure of the domestic power line carrier chip, the current power management applications occupy the mainstream in the market, followed by industrial control, security monitoring, broadband networks and other applications. In the coming years, driven by the concentrated release of smart grid construction demand, the power management market dominated by three-phase/single-phase carrier energy meters, carrier meter reading concentrators and other products will still occupy a major position; The industrial control applications represented by home burglar alarms such as smart home applications, downhole safety protection, LED street lighting control, precision agriculture, and pollution detection will gradually emerge.

The rise of home intelligence system has also opened up a new development platform for the development of PLC technology. In the current home smart system, the home intelligence system based on PC is the most popular. The concept of this system is that with the popularity of computers, all the data that household appliances need to be processed can be delivered to the PC. This requires building a data transmission network between home appliances and PCs. At present, the characteristics of “multi-wall” wireless network in the home environment seriously affect the transmission quality, especially in villas and penthouses. If a dedicated wired network is set up, besides increasing the cost, it will be very difficult and cumbersome to change the location of home appliances in daily life. This brings opportunities for power line carrier communication without re-routing.

How Electricity Cat Works

"Power cats" use the 1.6-3 Mbit/s frequency band to transmit signals. During transmission, the user data is modulated using GMSK or OFDM modulation technology, and then transmitted on the power line. At the receiving end, the modulated signal is first filtered by a filter, and then the original communication signal can be obtained after demodulation. Depending on the specific equipment, the currently available communication rate is 4.5-45 Mbit/s. The PLC device is a branch office and a modem. The central office is responsible for the communication with the internal PLC modem and the connection to the external network. During communication, the data from the user is modulated by the modem and transmitted to the central office equipment through the user's distribution line. The central office demodulates the signal and transfers it to the external Internet.

"Power cat" is a brand-new way of broadband Internet access, that is to "modulate" the network signal on the optical fiber to an ordinary household power socket, and let the signal be transmitted on the wire. Plug in the "power cat" on the power socket, it will separate the network signal on the wire; and then use the network cable to connect the "power cat" with the computer host network card socket to achieve online.