HomePlug is the family name for various power line communications specifications under the HomePlug designation, each with unique capabilities and compatibility with other HomePlug specifications.
Some HomePlug specifications target broadband applications. For instance in-home distribution of low data rate IPTV, gaming, and Internet content, while others focus on low power, low throughput and extended operating temperatures for applications such as smart power meters and in-home communications between electric systems and appliances. All of the HomePlug specifications were developed by the HomePlug Powerline Alliance, which also owns the HomePlug trademark.
On 18 October 2016 the HomePlug Alliance announced that all of its specifications would be put into the public domain and that other organizations would be taking on future activities relating to deployment of the existing technologies.[1] There was no mention in the announcement of any further technology development within the HomePlug community.
History
The HomePlug Powerline Alliance was formed to develop standards and technology for enabling devices to communicate with each other and the Internet over existing structure/house electrical wiring.
One of the greatest technical challenges was finding a way to reduce sensitivity to the electrical noise present on power lines. HomePlug solved this problem by increasing the communication carrier frequencies so that the signal is conveyed by the neutral conductor which is common to all phases.
The first HomePlug specification HomePlug 1.0 was released in June 2001. The HomePlug AV (for audio-video) specification released in 2005 increased physical layer (PHY) peak data rates from approximately 13.0Mbit/s[2] to 200Mbit/s. The HomePlug Green PHY specification was released in June 2010 and targets Smart Energy and Smart Grid applications as an interoperable "sibling" to HomePlug AV with lower cost, lower power consumption and decreased throughput.[3]
In 2010, the IEEE 1901 was approved and HomePlug AV as baseline technology for the FFT-OFDM PHY within the standard and became an international standard. The HomePlug Powerline Alliance is a certifying body for IEEE 1901 products. The three major specifications published by HomePlug (HomePlug AV, HomePlug Green PHY and HomePlug AV2) are interoperable and compliant.[4]
In 2011, the HomePlug Green PHY specification was adopted by Ford, General Motors, Audi, BMW, Daimler, Porsche, and Volkswagen, as a connectivity standard for Plug-In Electrical Vehicle.[5]
Newer versions of HomePlug support the use of Ethernet in bus topology via OFDM modulation, which enables several distinct data carriers to coexist in the same wire. Also, HomePlug's OFDM technology can turn off (mask) any sub-carriers that overlap previously allocated radio spectrum in a given geographic region, thus preventing interference. In North America, for instance, HomePlug AV only uses 917 of 1155 sub-carriers.[7]
Usage
Powerline networking is a network that can be set up using a building's existing electrical wiring. For electric vehicle charging, the SAE J1772 standard plug-in electric vehicle charger also requires HomePlug Green PHY to establish communications over a powerline before the vehicle can begin to draw any charging power.
All commercial HomePlug implementations meet the AES-128 encryption standard specified for advanced metering infrastructure by the US FERC. Accordingly, these devices are suitable to deploy as utility grade meters off the shelf with appropriate software.
As of late 2012, the most widely deployed HomePlug devices are "adapters", which are standalone modules that plug into wall outlets (or power strips [but not surge protectors] or extension cords) and provide one or more Ethernet ports. In a simple home network, the Internet gateway router connects via Ethernet cable to a powerline adapter, which in turn plugs into a nearby power outlet. A second adapter, plugged into any other outlet in the home, connects via Ethernet cable to any Ethernet device (e.g., computer, printer, IP phone, gaming station). Communications between the router and Ethernet devices are then conveyed over existing home electrical wiring. More complex networks can be implemented by plugging in additional adapters as needed. A powerline adapter may also be plugged into a hub or switch so that it supports multiple Ethernet devices residing in a common room.
Increasingly, the functionality found in standalone adapters is being built into end devices such as power control centers, digital media adapters, and Internet security cameras. It is anticipated that powerline networking functionality will be embedded in TVs, set-top boxes, DVRs, and other consumer electronics, especially with the emergence of global powerline networking standards such as the IEEE 1901 standard, ratified in September 2010.[8]
Several manufacturers sell devices that include 802.11n, HomePlug and four ports of Gigabit Ethernet connectivity for under US$100. Several are announced for early 2013 that also include 802.11ac connectivity, the combination of which with HomePlug is sold by Qualcomm Atheros as its Hy-Fi hybrid networking technology, an implementation of IEEE P1905. This permits a device to use wired Ethernet, powerline or wireless communication as available to provide a redundant and reliable failover– thought to be particularly important in consumer applications where there is no onsite expertise typically available to debug connections.
Versions
HomePlug 85Mbit/s adapter
HomePlug 1.0
The first HomePlug specification, HomePlug 1.0, provides a peak PHY-rate of 14Mbit/s. It was first introduced in June, 2001 and has since been replaced by HomePlug AV. On May 28, 2008 Telecommunications Industry Association (TIA) incorporated HomePlug 1.0 powerline technology into the newly published TIA-1113 international standard. TIA-1113 defines modem operations on user-premises electrical wiring. The new standard is the world's first multi-megabit powerline communications standard approved by an American National Standards Institute (ANSI)-accredited organization.[citation needed]
The HomePlug 1.0 MAC Layer uses channel access based on Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) to transport data from 46 to 1500 bytes long from encapsulated IEEE 802.3 frames as MAC Service Data Units (MSDUs) (so doesn't support jumbo frames).
HomePlug 1.0 Turbo adapters comply with the HomePlug 1.0 specification but employ a faster, proprietary mode that increases the peak PHY-rate to 85Mbit/s. HomePlug 1.0 Turbo modems were only available from Intellon Corporation.
HomePlug AV
The HomePlug AV specification, which was introduced in August 2005, provides sufficient bandwidth for applications such as HDTV and VoIP. HomePlug AV offers a peak data rate of 200Mbit/s at the physical layer, and about 80Mbit/s at the MAC layer. HomePlug AV devices are required to coexist, and optionally to interoperate, with HomePlug 1.0 devices. The physical layer uses OFDM carriers spaced at 24.414kHz, with carriers from 2 to 30MHz. Depending on the signal to noise ratio, the system automatically selects from BPSK, QPSK, 16 QAM, 64 QAM, 256 QAM, and 1024 QAM, on a carrier by carrier basis.
Utilizing adaptive modulation on up to 1155 OFDM sub-carriers, turbo convolution codes for error correction, two-level MAC framing with ARQ,[9] and other techniques, HomePlug AV can achieve near the theoretical maximum bandwidth across a given transmission path.[7] For security reasons, the specification includes key distribution techniques and the use of 128 bit AES encryption. Furthermore, the specification's adaptive techniques present inherent obstacles to eavesdropping and cyber attacks.[10][11]
Some Qualcomm Atheros-based adapters comply with the HomePlug AV specification but employ a proprietary extension that increases the PHY-rate to 500Mbit/s primarily by using a wider spectrum.[12]
HomePlug AV2
The HomePlug AV2 specification was introduced in January 2012. It is interoperable with HomePlug AV and HomePlug GreenPHY devices and is IEEE 1901 standard compliant. It features gigabit-class PHY-rate, support for MIMO PHY, repeating functionalities and power saving modes.[4][13] It can additionally use the band from 30 to 86MHz. The first generation are generally considered to be 20% faster than HomePlug AV 500, it is often sold as HomePlug 600. They do not support MIMO, but only single streams due to the Atheros chipset architecture (QCA7450/AR1540). October 2013 Qualcomm announced the QCA7500 with support for 2x2 MIMO which supposedly will double data transfer rates. In 2014, Qualcomm began production of the QCA7500. This device provided raw PHY rates of 1300Mbit/s, with resultant data rates of 550Mbit/s UDP and 500Mbit/s TCP, full MIMO. Communication takes place on both the line–neutral and line–ground power line pairs. Devolo from Germany has made proprietary improvements on the standard, and are using the ground wire in addition to phase (also known as hot or live) and null (also known as neutral). This technology is available worldwide, though can only be used in territories that use the ground wire in their building wiring regulations.[citation needed]
HomePlug Green PHY
The HomePlug Green PHY specification is a subset of HomePlug AV that is intended for use in the smart grid. It has peak rates of 10Mbit/s and is designed to go into smart meters and smaller appliances such as HVAC thermostats, home appliances and plug-in electric vehicles[14] so that data can be shared over a home network and with the power utility. High capacity broadband is not needed for such applications; the most important requirements are low power and cost, reliable communication, and compact size. GreenPHY uses up to 75% less energy than AV.[14]
The HomePlug Powerline Alliance worked with utilities and meter manufacturers to develop this 690-page specification.[15] HomePlug Green PHY devices are required to be fully interoperable with devices based on HomePlug AV, HomePlug AV2 and IEEE 1901 specification, which is considered[by whom?] to hamper their power consumption and cost reduction. The HomePlug silicon vendor QualComm announced commercially available Green PHY silicon in December 2011.[16]
Access Broadband Power Line (BPL) refers to a to-the-home broadband access technology. The HomePlug Alliance formed the HomePlug Access BPL Working Group, whose first charter was to develop the Market Requirements Document (MRD) for a HomePlug Access BPL specification. The Alliance made an open invitation to the BPL industry to participate in the development of or provide input for consideration in the MRD. After several months of collaboration between utilities, ISPs and other BPL industry groups, the MRD was completed in June 2005. HomePlug's work on the Access BPL was subsequently contributed and merged into the IEEE 1901 standard.[3]
Security
Since signals may travel outside the user's residence or business and be eavesdropped on, HomePlug includes the ability to set an encryption password. The HomePlug specification requires that all devices are set to a default out-of-box password– although a common one. Users should change this password. If the password is not changed, an attacker can use their own homeplug device to detect the users signals, and then use the default password to access and change settings such as the encryption key used.
On many new powerline adapters that come as a boxed pair, a unique security key has already been established and the user does not need to change the password, except when using these with existing powerline adapters, or adding new adapters to an existing network. Some systems support an authenticate button, allowing adapters to be added to the network with just two button presses (one of each of the devices).
To simplify the process of configuring passwords on a HomePlug network, each device has a built-in master password, chosen at random by the manufacturer and hard-wired into the device, which is used only for setting the encryption passwords. A printed label on the device lists its master password.
The HomePlug AV standard uses 128-bit AES, while the older versions use the less secure DES protocols. This encryption has no effect on the data the user sends or receives, and therefore higher-level protocols and systems like TLS should still be used.
Since HomePlug devices typically function as transparent network bridges, computers running any operating system can use them for network access. However, some manufacturers only supply the password-setup software in a Microsoft Windows version; in other words, enabling encryption requires a computer running Windows Archived 2006-07-20 at the Wayback Machine . Once the encryption password has been configured, any device supporting the Ethernet specification will work on the adapter.
Interoperability
HomePlug AV, GP and AV2 are fully interoperable, and will also interoperate with IEEE 1901 devices. HomePlug 1.0 devices do not interoperate with HomePlug AV devices. Although it is technically possible to achieve such backward compatibility, doing so is not economically feasible because of the high cost of circuitry that would have to support different forward error correction (FEC) techniques and feature sets.[17]
HomePlug devices will not interoperate with devices that employ other powerline technologies, such as Universal Powerline Association (UPA), HD-PLC, or G.hn. In the case of G.hn, it was deemed prohibitively expensive to implement both HomePlug's turbo codingforward error correction and G.hn's low-density parity-check code.[18] However, IEEE 1901 allows co-existence within the same deployment of both HomePlug AV and HD-PLC via its Inter-System Protocol (ISP). G.hn also supports the ISP.
HomePlug devices are not compatible with certain power strips, surge protectors, and uninterruptible power supplies incorporating filters, which block the high-frequency signal. In such cases, the installer must plug devices directly into building electrical receptacles.[19] If a spare power point is not available, a double adapter can be used in many cases with the incompatible device on one side and the HomePlug device on the other.
One of the concerns with all powerline systems, when compared to dedicated data wiring, is that the route of the wiring is not known in advance, and is generally already optimized for power transmission. This means that there will be situations where the system will radiate a significant fraction of the energy, in the form of radio frequency interference, or be vulnerable to the ingress of external signals. Given that the shortwave band is used both by low-power long-range telemetry and high-power broadcast signals, this is a potentially serious drawback. To attempt to minimize the effects of incoming interference and frequency-dependent path losses, the HomePlug standard requires each node to maintain 'tone maps' updates during operation, so the equipment 'learns' to avoid certain troublesome frequencies and to put more data onto those frequencies that exhibit a low loss. However, while this mitigates against ingress, if there is sensitive receiving equipment nearby then there is no easy way to tell the HomePlug apparatus to 'turn down' the radiated interference. In comparison to the received signals in a radio communication equipment, the signal levels in a powerline system are quite high. Typically the power density is 10nW/Hz, as each carrier occupies a channel of 24kHz, each carrier is injected at a level of −6.6dBm (220 microwatts), making the total full channel power 24dBm, (250 milliwatts). [citation needed]
In the UK there have been suggestions that users of powerline equipment should be prosecuted under the Wireless Telegraphy Act, if they cause interference to official radio systems.[20] Also GCHQ has published concerns that such interference affects its ability to monitor radio activity in the UK.[21]
In telecommunications, orthogonal frequency-division multiplexing (OFDM) is a type of digital transmission used in digital modulation for encoding digital (binary) data on multiple carrier frequencies. OFDM has developed into a popular scheme for wideband digital communication, used in applications such as digital television and audio broadcasting, DSL internet access, wireless networks, power line networks, and 4G/5G mobile communications.
Ethernet over twisted-pair technologies use twisted-pair cables for the physical layer of an Ethernet computer network. They are a subset of all Ethernet physical layers.
In computer networking, Fast Ethernet physical layers carry traffic at the nominal rate of 100 Mbit/s. The prior Ethernet speed was 10 Mbit/s. Of the Fast Ethernet physical layers, 100BASE-TX is by far the most common.
Power-line communication (PLC) is the carrying of data on a conductor that is also used simultaneously for AC electric power transmission or electric power distribution to consumers. The line that does so is known as a power-line carrier.
IEEE 802.20 or Mobile Broadband Wireless Access (MBWA) was a specification by the standard association of the Institute of Electrical and Electronics Engineers (IEEE) for mobile broadband networks. The main standard was published in 2008. MBWA is no longer being actively developed.
Broadband over power lines (BPL) is a method of power-line communication (PLC) that allows relatively high-speed digital data transmission over public electric power distribution wiring. BPL uses higher frequencies, a wider frequency range, and different technologies compared to other forms of power-line communications to provide high-rate communication over longer distances. BPL uses frequencies that are part of the radio spectrum allocated to over-the-air communication services; therefore, the prevention of interference to, and from, these services is a very important factor in designing BPL systems.
The HomePlug Powerline Alliance is a trade association of electronics manufacturers, service providers, and retailers that establishes standards for, and tests members' devices for compliance to, the various power line communication technologies known as HomePlug.
The media-independent interface (MII) was originally defined as a standard interface to connect a Fast Ethernet medium access control (MAC) block to a PHY chip. The MII is standardized by IEEE 802.3u and connects different types of PHYs to MACs. Being media independent means that different types of PHY devices for connecting to different media can be used without redesigning or replacing the MAC hardware. Thus any MAC may be used with any PHY, independent of the network signal transmission medium.
IEEE 1901 is a standard for high-speed communication devices via electric power lines, often called broadband over power lines (BPL). The standard uses transmission frequencies below 100 MHz. This standard is usable by all classes of BPL devices, including BPL devices used for the connection to Internet access services as well as BPL devices used within buildings for local area networks, smart energy applications, transportation platforms (vehicle), and other data distribution applications.
A home network or home area network (HAN) is a type of computer network that facilitates communication among devices within the close vicinity of a home. Devices capable of participating in this network, for example, smart devices such as network printers and handheld mobile computers, often gain enhanced emergent capabilities through their ability to interact. These additional capabilities can be used to increase the quality of life inside the home in a variety of ways, such as automation of repetitive tasks, increased personal productivity, enhanced home security, and easier access to entertainment.
Qualcomm Atheros is a developer of semiconductor chips for network communications, particularly wireless chipsets. The company was founded under the name T-Span Systems in 1998 by experts in signal processing and VLSI design from Stanford University, the University of California, Berkeley, and private industry. The company was renamed Atheros Communications in 2000 and it completed an initial public offering in February 2004, trading on the NASDAQ under the symbol ATHR.
The Multimedia over Coax Alliance (MoCA) is an international standards consortium that publishes specifications for networking over coaxial cable. The technology was originally developed to distribute IP television in homes using existing cabling, but is now used as a general-purpose Ethernet link where it is inconvenient or undesirable to replace existing coaxial cable with optical fiber or twisted pair cabling.
The physical-layer specifications of the Ethernet family of computer network standards are published by the Institute of Electrical and Electronics Engineers (IEEE), which defines the electrical or optical properties and the transfer speed of the physical connection between a device and the network or between network devices. It is complemented by the MAC layer and the logical link layer. An implementation of a specific physical layer is commonly referred to as PHY.
Ethernet in the first mile (EFM) refers to using one of the Ethernet family of computer network technologies between a telecommunications company and a customer's premises. From the customer's point of view, it is their first mile, although from the access network's point of view it is known as the last mile.
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A wireless repeater is a device that takes an existing signal from a wireless router or wireless access point and rebroadcasts it to create a second network. When two or more hosts have to be connected with one another over the IEEE 802.11 protocol and the distance is too long for a direct connection to be established, a wireless repeater is used to bridge the gap. It can be a specialized stand-alone computer networking device. Also, some wireless network interface controllers (WNIC)s optionally support operating in such a mode. Those outside of the primary network will be able to connect through the new "repeated" network. However, as far as the original router or access point is concerned, only the repeater MAC is connected, making it necessary to enable safety features on the wireless repeater. Wireless repeaters are commonly used to improve signal range and strength within homes and small offices.
IEEE 802.11g-2003 or 802.11g is an amendment to the IEEE 802.11 specification that operates in the 2.4 GHz microwave band. The standard has extended link rate to up to 54 Mbit/s using the same 20 MHz bandwidth as 802.11b uses to achieve 11 Mbit/s. This specification, under the marketing name of Wi‑Fi, has been implemented all over the world. The 802.11g protocol is now Clause 19 of the published IEEE 802.11-2007 standard, and Clause 19 of the published IEEE 802.11-2012 standard.
Ethernet over Coax (EoC) is a family of technologies that supports the transmission of Ethernet frames over coaxial cable. The Institute of Electrical and Electronics Engineers (IEEE) maintains all official Ethernet standards in the IEEE 802 family.
IEEE 1905.1 is an IEEE standard which defines a network enabler for home networking supporting both wireless and wireline technologies: IEEE 802.11, IEEE 1901 power-line networking, IEEE 802.3 Ethernet and Multimedia over Coax (MoCA).
SiConnect was a powerline communications technology business that built low-cost, high performance broadband modem silicon using its proprietary POEM technology. It is most notable now for contributing its Arbitration-Determined Multiplexing technology to the IEEE P1901 draft specification for co-existence between disparate powerline technologies.
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