HomePlug

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HomePlug is a brand for specifications of carrier frequency systems for in-house Power Line Communication or PowerLAN . The specifications are based on patents owned by Atheros (formerly Intellon), which designs and manufactures integrated circuits for carrier frequency systems.

HomePlug 1.0 adapters are e.g. B. from Acer , Allnet, Corinex, devolo , Prevola or Netgear and have either an RJ45 (Ethernet) or USB socket or audio cinch socket combination.

HomePlug 85Mbps adapter

functionality

HomePlug functionality

The power grid of a house provides the lines for transporting the data signals. Data can be sent and received in any room with a power socket. The necessary adapters are inserted as normal plug in the socket and by a network cable to the network card of a computer connected or other device with a network connection. At least two such adapters are required. HomePlug devices have been sold in Germany since 2003.

Newer models work according to the new HomePlug AV specification and offer a data transfer rate of max. 200 Mbit / s (e.g. adapters from devolo or those based on a chipset from DS2 , which have already been introduced with up to 400 Mbit / s). The new specification " HomePlug AV " (not HomePlug 2.0, AV stands for "Audio / Video") enables video streaming in DVD quality. HomePlug AV devices may or may not be compatible with HomePlug 1.0 devices. Whether the data exchange between devices with different specifications works depends on whether the HomePlug AV devices have a corresponding compatibility mode. Regardless of this, the two systems can be operated alongside one another in the same power grid without interference, so they are always coexistent.

The mains voltage of 230 V is superimposed with carrier frequencies of 4.5 to 27 MHz (HomePlug) or 2 to 32 MHz (DS2), which are modulated with the useful signal in the OFDM process .

The topology is a bus structure, i. This means that all devices are connected to the same line and only one device can send or receive at a time (cf. 10BASE2 ). HomePlug 1.0 uses the CSMA / CA process to handle collisions (two stations want to send data at the same time) . HomePlug AV , on the other hand, should also be able to use the more complex, but more powerful TDMA method in the future , which does not have any collisions. Mixed operation of HomePlug 1.0 (CSMA / CA) and HomePlug AV (TDMA) should then also be possible, even without any losses for the HPAV (HomePlug AV) adapters involved. However, interoperability is only an optional feature; the specification does not provide for a requirement.

The range should be around 300 m, but this depends on the quality of the lines in the house and the devices or sources of interference in the power grid. Furthermore, the range is usually limited by the electricity meter . Its signal attenuation is often so great that it is hardly possible to transmit data beyond it, for example to neighboring apartments. However, the electricity meter is not always an obstacle; in many cases, data can be received across two electricity meters. It is therefore recommended to configure a different network name in the devices. However, due to the inevitable radiation of high-frequency signals on unshielded power lines, the data can also be received within a large area of ​​the actual installation. Some manufacturers of HomePlug devices use notch filters to keep sensitive shortwave applications free from interference.

The three-phase alternating current , which is common in many European households, can also cause difficulties . Whether the communication between circuits that are connected to different phases works depends on the local conditions and cannot generally be assumed.

The use of HomePlug adapters on extension cables and multiple sockets is also problematic, as these are often equipped with integrated surge arresters. These can lead to high attenuation and prevent data transmission.

Areas of application

The technology is used in small LANs and home networks. Such devices are increasingly being used in professional applications, whereby not only in-house power lines, but also coaxial cables (antenna cables) are used for data transmission.

HomePlug 1.0 is mainly used for data and audio transmission. The HomePlug 1.0 specification theoretically achieves a transmission of up to 14 Mbit / s and a max. Range of 200–300 m within one circuit . This way, several floors can be bridged.

advantages

Technologies like HomePlug offer an alternative to other network technologies like Ethernet or WLAN . Your advantages are that no new cables have to be laid and the range can be greater than with WLAN without any special effort. The technology makes it possible to "extend" an Internet connection from the modem or router to another room. Since several adapters can be operated in a house power network, a home network can be set up easily. To do this, an adapter must be plugged into the nearest socket for each PC and connected to the PC.

Networking with this type of technology has advantages, especially if a network cable cannot be laid on site and WLAN does not work due to thick walls and ceilings.

disadvantage

Carrier frequency systems for supplying households with Internet access via the power line are controversial, since their use with unshielded lines leads to the emission of high-frequency electromagnetic waves. HomePlug works with significantly lower transmission levels than the test systems of the energy supply companies, but in practice the signals are expected to be emitted beyond the boundaries of the apartment or property.

In the operating instructions for the HomePlug devices you will usually find a notice similar to the following: “This device can cause radio interference in living areas; In this case, the operator can be required to take appropriate measures. ”This should usually be the decommissioning of the HomePlug devices. In the event of faults, you can contact the Federal Network Agency's radio measurement service .

The data transmission can also be monitored. This is why data encryption is usually used.

Since the quality of the communication connection between the individual nodes of a HomePlug network depends on the electrical wiring and is prone to failure (e.g. large loads), it must be expected that connections will be poor or not at all or that there will be temporary disruptions occur.

variants

HomePlug 1.0

The original specification was introduced by the HomePlug Alliance in June 2001. It supports up to 14 Mbit / s, but there were several extensions that brought higher speed, in a common variant up to 85 Mbit / s. HomePlug 1.0 was incorporated into the TIA-1113 standard in 2008 ("Medium-Speed ​​(up to 14 Mbps) Power Line Communications (PLC) Modems using Windowed OFDM").

HomePlug Access BPL

HomePlug "Access Broadband Power Line" was created in cooperation with power suppliers who want to offer households a broadband connection via the house cable. The requirements document was presented in June 2005, the further specification has been delayed and was then concluded as "IEEE1901 Access" as part of the IEEE 1901 standardization.

HomePlug AV

HomePlug AV was introduced by the HomePlug Alliance in August 2005. The specification allows up to 200 Mbit / s and also allows HDTV content to be transmitted. HomePlug AV devices do not necessarily have to be backwards compatible with HomePlug 1.0, but must not interfere with HomePlug 1.0 connections on the same cable.

HomePlug AV2

The expansion under the title "AV2" was presented in November 2009. The specification allows up to 600 Mbit / s and has been in the final version since January 2012. The specification was developed together with IEEE 1901 , which took several rounds of standardization until Draft 4.0 was approved as the final standard on December 30, 2010. HomePlug AV2 devices are said to be backwards compatible with HomePlug AV devices, but bring an additional wavelet PHY that allows operation in Japan.

HomePlug GreenPHY

HomePlug GreenPHY is being developed as part of the ISO / IEC 15118-3 standardization of smart grid applications (“intelligent power grid”) and is intended for vehicle-to-grid communication in electric cars . The main goal of the development is cheaper and energy-saving adapters to equip home devices with them as standard, which can then communicate via a robust protocol in the networked house ("intelligent living"). The draft phase was completed in February 2011 and is available for voting; publication is scheduled for September 2011. HomePlug GreenPHY is designed to be compatible with AV2 (and therefore AV).

Individual evidence

  1. ↑ Legal & Privacy Policy . HomePlug Powerline Alliance Incorporated. Retrieved May 10, 2009.
  2. ↑ HomePlug® PLC . Atheros (formerly Intellon Corporation). Archived from the original on May 3, 2012. Retrieved April 26, 2012.
  3. ↑ White Paper from www.homeplug.org ( Memento July 4, 2007 in the Internet Archive )
  4. ↑ Involuntary network neighbors thanks to Powerline. Heise Online. Retrieved May 12, 2009.
  5. ↑ The room shines thanks to HomePlug.
  6. ↑ HomePlug Green PHY ™ specification - HomePlug Powerline Alliance at www.homeplug.org , accessed December 30, 2013.

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