HomePlug
Encyclopedia
HomePlug is the family name for various power line communication
s specifications that support networking over existing home electrical wiring. Several specifications exist under the HomePlug moniker, with each offering unique performance capabilities and coexistence or compatibility with other HomePlug specifications.
Some HomePlug specifications target broadband applications such as 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.
The first HomePlug specification, HomePlug 1.0, was released in June 2001. The HomePlug AV specification, which was released in 2005, increased physical layer (PHY) peak data rates from 14 to 200 Mbit/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. (HomePlug Command and Control low frequency specification was released in 2007, but later deprecated and replaced by HomePlug Green PHY.)
On September 30, 2010, the IEEE’s 1901 Broadband Powerline Standard was approved and HomePlug AV, as baseline technology for the FFT-OFDM PHY within the standard, is now ratified and validated as 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 the forthcoming HomePlug AV2) are interoperable and compliant. As of November 2011, there are 4 chip vendors that are shipping interoperable HomePlug AV chipsets with IEEE 1901 support (Broadcom, Qualcomm Atheros, Sigma Designs, and SPiDCOM) and millions of units are shipped each month throughout the world. Many HomePlug AV products are shipping from key vendors such as Cisco, devolo, D-Link, Logitech, NETGEAR and Western Digital. Major IPTV service providers such as France Telecom, British Telecom, and Deutsche Telekom are also shipping large volumes of HomePlug products. In November 2011, the HomePlug Green PHY specification was adopted by 7 key American and German automobile companies, Ford, General Motors, Audi, BMW, Daimler, Porche, and Volkswagen, as a connectivity standard for Plug-In Electrical Vehicle.
Newer versions of HomePlug support the use of Ethernet in bus topology. This is achieved by means of OFDM modulation that 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.
The most widely deployed powerline networking devices are "adapters", which are standalone modules that plug into wall outlets (or power strips 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, could connect via Ethernet cable to any Ethernet-enabled device (e.g., computer, printer, IP
phone, gaming station). Data communications between the router and Ethernet devices would be conveyed over existing home electrical wiring. More complex networks with multiple adapters 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..
(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.
There are also HomePlug 1.0 with Turbo adapters that still may be found on the market. These comply with the HomePlug 1.0 specification but feature a faster, proprietary mode that increases the peak PHY-rate to 85 Mbit/s.
Utilizing adaptive modulation on up to 1155 OFDM sub-carriers, turbo convolution codes for error correction
, two-level MAC
framing with ARQ, and other techniques, HomePlug AV can achieve near the theoretical maximum bandwidth across a given transmission path. 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.
speed at the physical layer and 600Mbs+ at the MAC layer. The AV2 spec is expected to be completed in mid 2011, with products expected to ship in late 2011. Completion of the HomePlug AV2 Marketing Requirements Document
was announced in November 2009.
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 data at either end (Ethernet side) of the HomePlug link is not encrypted (unless an encrypted higher-layer protocol such as TLS
or IPsec
is being used), only the link between HomePlug devices is encrypted. The HomePlug AV standard uses 128-bit AES
, while the older versions use the less secure DES
.
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 http://www.netgear.com/products/details/XE102.php. Once the encryption password has been configured, Windows will no longer be needed, so in the case of a network where all computers run other systems a borrowed laptop could be used for initial setup purposes.
HomePlug 1.0 devices do not interoperate with HomePlug AV devices. Although it is technically possible to achieve backward compatibility, this 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. HomePlug AV, GP, and AV2 are fully interoperable, and will also interoperate with the IEEE 1901 devices.
Similarly, HomePlug (1.0, GP, AV, AV2) devices will not interoperate with products based on the G.hn
standard (for power lines, phone lines and coaxial cables) developed by ITU-T
because it was deemed prohibitively expensive to implement both HomePlug's turbo coding forward error correction
and the low density parity check
(LDPC) proposed for G.hn.
Power line communication
Power line communication or power line carrier , also known as power line digital subscriber line , mains communication, power line telecom , power line networking , or broadband over power lines are systems for carrying data on a conductor also used for electric power transmission.A wide range...
s specifications that support networking over existing home electrical wiring. Several specifications exist under the HomePlug moniker, with each offering unique performance capabilities and coexistence or compatibility with other HomePlug specifications.
Some HomePlug specifications target broadband applications such as 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
HomePlug Powerline Alliance
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 alliance developed standards...
, which also owns the HomePlug trademark.
History
From its inception, the HomePlug Alliance has delivered technology that enables products to use existing home electrical wiring to communicate with each other and connect to the Internet. One of the greatest technical challenges was finding a way to reduce sensitivity to the electrical noise that is inevitably present on power lines. Whenever an appliance is turned on or off, it creates electrical noise that can interfere with data transfer through the wiring. Noise sensitivity was problematic in early powerline technology, though later versions have solved this problem. Also, earlier powerline technology could not reliably pass the communication signal through different electrical phases. HomePlug has solved this issue by increasing the communication carrier frequencies so that the signal will be 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 specification, which was released in 2005, increased physical layer (PHY) peak data rates from 14 to 200 Mbit/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. (HomePlug Command and Control low frequency specification was released in 2007, but later deprecated and replaced by HomePlug Green PHY.)
On September 30, 2010, the IEEE’s 1901 Broadband Powerline Standard was approved and HomePlug AV, as baseline technology for the FFT-OFDM PHY within the standard, is now ratified and validated as 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 the forthcoming HomePlug AV2) are interoperable and compliant. As of November 2011, there are 4 chip vendors that are shipping interoperable HomePlug AV chipsets with IEEE 1901 support (Broadcom, Qualcomm Atheros, Sigma Designs, and SPiDCOM) and millions of units are shipped each month throughout the world. Many HomePlug AV products are shipping from key vendors such as Cisco, devolo, D-Link, Logitech, NETGEAR and Western Digital. Major IPTV service providers such as France Telecom, British Telecom, and Deutsche Telekom are also shipping large volumes of HomePlug products. In November 2011, the HomePlug Green PHY specification was adopted by 7 key American and German automobile companies, Ford, General Motors, Audi, BMW, Daimler, Porche, and Volkswagen, as a connectivity standard for Plug-In Electrical Vehicle.
Newer versions of HomePlug support the use of Ethernet in bus topology. This is achieved by means of OFDM modulation that 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
Radio spectrum
Radio spectrum refers to the part of the electromagnetic spectrum corresponding to radio frequencies – that is, frequencies lower than around 300 GHz ....
in a given geographic region, thus preventing interference. In North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, for instance, HomePlug AV only uses 917 of 1155 sub-carriers.
Usage
The major benefit of powerline networking is that users can easily establish a network using a home's existing electrical wiring as the communication medium. There is no need to drill holes in walls or ceiling to route new wiring and, as a result, installation is quick, easy and relatively inexpensive. In most homes throughout most geographies, power outlets are found in most rooms. For AC-powered devices that must already be near an outlet, powerline networking is a natural and easily accomplished networking method.The most widely deployed powerline networking devices are "adapters", which are standalone modules that plug into wall outlets (or power strips 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, could connect via Ethernet cable to any Ethernet-enabled device (e.g., computer, printer, IP
Internet Protocol
The Internet Protocol is the principal communications protocol used for relaying datagrams across an internetwork using the Internet Protocol Suite...
phone, gaming station). Data communications between the router and Ethernet devices would be conveyed over existing home electrical wiring. More complex networks with multiple adapters 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
IEEE P1901
The IEEE 1901 working group of the Institute of Electrical and Electronics Engineers develops standards for high speed power line communications....
standard, ratified in September 2010..
HomePlug 1.0
HomePlug 1.0 was the first HomePlug specification. It provides a peak PHY-rate of 14 Mbit/s. It was first introduced in June, 2001 and has since been replaced by HomePlug AV. On May 28, 2008 Telecommunications Industry AssociationTelecommunications Industry Association
The Telecommunications Industry Association is accredited by the American National Standards Institute to develop voluntary, consensus-based industry standards for a wide variety of ICT products, and currently represents nearly 400 companies...
(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.
There are also HomePlug 1.0 with Turbo adapters that still may be found on the market. These comply with the HomePlug 1.0 specification but feature a faster, proprietary mode that increases the peak PHY-rate to 85 Mbit/s.
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 200 Mbs at the physical layer, and about 80 Mbs at the MAC layer. HomePlug AV devices are required to coexist, and optionally to interoperate, with HomePlug 1.0 devices.Utilizing adaptive modulation on up to 1155 OFDM sub-carriers, turbo convolution codes for error correction
Forward error correction
In telecommunication, information theory, and coding theory, forward error correction or channel coding is a technique used for controlling errors in data transmission over unreliable or noisy communication channels....
, two-level MAC
Media Access Control
The media access control data communication protocol sub-layer, also known as the medium access control, is a sublayer of the data link layer specified in the seven-layer OSI model , and in the four-layer TCP/IP model...
framing with ARQ, and other techniques, HomePlug AV can achieve near the theoretical maximum bandwidth across a given transmission path. For security reasons, the specification includes key distribution
Key distribution
In symmetric key cryptography, both parties must possess a secret key which they must exchange prior to using any encryption. Distribution of secret keys has been problematic until recently, because it involved face-to-face meeting, use of a trusted courier, or sending the key through an existing...
techniques and the use of 128 bit AES
Advanced Encryption Standard
Advanced Encryption Standard is a specification for the encryption of electronic data. It has been adopted by the U.S. government and is now used worldwide. It supersedes DES...
encryption. Furthermore, the specification's adaptive techniques present inherent obstacles to eavesdropping and cyber attacks.
HomePlug AV2
The HomePlugAV2 project is currently under development and is the next generation for the HomePlug line. Current estimates state that it will operate upon a 600 Mbit/s transfer capability. HomePlug AV2 is fully interoperable with HomePlug AV and will be brought into the IEEE 1901 standard once the specification is completed. HomePlug AV2 offers GigabitGigabit
The gigabit is a multiple of the unit bit for digital information or computer storage. The prefix giga is defined in the International System of Units as a multiplier of 109 , and therefore...
speed at the physical layer and 600Mbs+ at the MAC layer. The AV2 spec is expected to be completed in mid 2011, with products expected to ship in late 2011. Completion of the HomePlug AV2 Marketing Requirements Document
Marketing Requirements Document
A market requirements document in project management and systems engineering, is a document that expresses the customer's wants and needs for the product or service.It is typically written as a part of product marketing or product management...
was announced in November 2009.
HomePlug GreenPhy
HomePlug Green PHY is a new specification that is a subset of HomePlug AV and is specifically designed for the requirements of the smart grid market. It has peak rates of 10 Mbit/s and is designed to go into smart meters and smaller appliances such as HVAC/thermostats,, home appliances and plug-in electric hybrid vehicles. so that data can be shared over a Home Area Network (HAN) and back to the utility. For these applications, there’s not a great need for high capacity broadband; the most important requirements are for lower power, robust, reliable coverage throughout the home, smaller size and less costly Bill of Materials. GreenPHY uses up to 75% less energy than AV. The HomePlug Powerline Alliance worked closely with utilities and meter manufacturers to develop this 700-page specification (downloadable from the HomePlug website). HomePlug Green PHY-based products will be fully interoperable with products based on HomePlug AV, IEEE 1901 or the upcoming HomePlug AV2 specification.HomePlug Access BPL
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.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. 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, unless using these with existing powerline adapters, or adding new adapters. Some manufacturers supply adapters with security key buttons on them, allowing users to easily set unique security keys by plugging each unit in one at a time and pressing the button on the front (see more detailed instructions that come with the units).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 data at either end (Ethernet side) of the HomePlug link is not encrypted (unless an encrypted higher-layer protocol such as TLS
TLS
-Computing:* Transport Layer Security, a network protocol and successor to Secure Sockets Layer * Thread-local storage, a mechanism for allocating variables in computer science...
or IPsec
IPsec
Internet Protocol Security is a protocol suite for securing Internet Protocol communications by authenticating and encrypting each IP packet of a communication session...
is being used), only the link between HomePlug devices is encrypted. The HomePlug AV standard uses 128-bit AES
AES
AES may refer to:Standards, systems, and methods* Application Environment Services, a component of Digital Research's GEM windowing system* The Advanced Encryption Standard...
, while the older versions use the less secure DES
DES
-Computing:* Data Encryption Standard* DirectShow Editing Services, an Application Programming Interface-Medical:* Diethylstilbestrol, a synthetic estrogen and the origin of the phrase "DES daughter"* DES gene, which encodes the Desmin protein...
.
Since HomePlug devices typically function as transparent network bridges, computers running any operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer 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 http://www.netgear.com/products/details/XE102.php. Once the encryption password has been configured, Windows will no longer be needed, so in the case of a network where all computers run other systems a borrowed laptop could be used for initial setup purposes.
Interoperability
Products are tested for interoperability and certified based on the HomePlug specification and the IEEE 1901 powerline standard. Devices marked with the HomePlug certification mark will interoperate with each other, but not with devices that employ other powerline technologies such as UPA (silicon vendor Marvell) or HD-PLC (silicon vendor Panasonic), which are found primarily in Japan.HomePlug 1.0 devices do not interoperate with HomePlug AV devices. Although it is technically possible to achieve backward compatibility, this is not economically feasible because of the high cost of circuitry that would have to support different Forward error correction
Forward error correction
In telecommunication, information theory, and coding theory, forward error correction or channel coding is a technique used for controlling errors in data transmission over unreliable or noisy communication channels....
(FEC) techniques and feature sets. HomePlug AV, GP, and AV2 are fully interoperable, and will also interoperate with the IEEE 1901 devices.
Similarly, HomePlug (1.0, GP, AV, AV2) devices will not interoperate with products based on the G.hn
G.hn
G.hn is the common name for a home network technology family of standards developed under the International Telecommunication Union's Standardization arm and promoted by the HomeGrid Forum...
standard (for power lines, phone lines and coaxial cables) developed by ITU-T
ITU-T
The ITU Telecommunication Standardization Sector is one of the three sectors of the International Telecommunication Union ; it coordinates standards for telecommunications....
because it was deemed prohibitively expensive to implement both HomePlug's turbo coding forward error correction
Forward error correction
In telecommunication, information theory, and coding theory, forward error correction or channel coding is a technique used for controlling errors in data transmission over unreliable or noisy communication channels....
and the low density parity check
Low-density parity-check code
In information theory, a low-density parity-check code is a linear error correcting code, a method of transmitting a message over a noisy transmission channel, and is constructed using a sparse bipartite graph...
(LDPC) proposed for G.hn.
See also
- IEEE 1901
- Multimedia over Coax AllianceMultimedia over Coax AllianceMultimedia over Coax Alliance is a trade group promoting a standard that uses coaxial cables to connect consumer electronics and home networking devices in homes. It allows both data communication and the transfer of audio and video streams....
- Power line communicationPower line communicationPower line communication or power line carrier , also known as power line digital subscriber line , mains communication, power line telecom , power line networking , or broadband over power lines are systems for carrying data on a conductor also used for electric power transmission.A wide range...
- Power over EthernetPower over EthernetPower over Ethernet or PoE technology describes a system to pass electrical power safely, along with data, on Ethernet cabling. The IEEE standard for PoE requires category 5 cable or higher for high power levels, but can operate with category 3 cable for low power levels...