The IEEE 1901 working group of the Institute of Electrical and Electronics Engineers develops standards for high speed power line communications. This technology allows computer networks to send data over electrical power lines (contrasting with approaches such as power over Ethernet which send power over computer network wires). The group formed in 2005, approved its medium access control and physical layer (PHY) draft specifications in 2009, and published its first standard in 2010.
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The 1901 standards include two different physical layers, one based on orthogonal frequency-division multiplexing (OFDM) modulation and another based on wavelet modulation. Each PHY is optional, and implementers of the specification may, but are not required to include both. Devices that use the OFDM PHY only would not interoperate with devices based on Wavelet PHY. Some members maintain that this lack of interoperability defeats the purpose of having a standard.[1] Others maintain that it is a necessary step to market consolidation.[2] The OFDM PHY is derived from HomePlug AV technology and is deployed in HomePlug-based products. The Wavelet PHY is more narrowly deployed, primarily in Japan.
The first option ("FFT PHY") is based on FFT OFDM modulation, with a forward error correction (FEC) scheme based on Convolutional turbo code (CTC). The second option ("Wavelet PHY") is based on Wavelet OFDM modulation, with a mandatory FEC based on concatenated Reed-Solomon (RS) and Convolutional code, and an option to use Low-Density Parity-Check (LDPC) code.[3]
On top of these two physical layers, two different MAC layers were defined; one for In-home networking and the other for Access Networking[4]. Two MACs were needed because each application has its unique and different requirements.
The project was first authorized in June 2005.[5] In October 2007 the working group completed selection process. The final proposal selected by the group was a combined HomePlug proposal and Panasonic proposal known as HD-PLC. All other proposals were eliminated.[6]
In December 2008 the working group voted to adopt the baseline with broad support (85% for the in-home cluster, 97% for the access cluster and 100% for the coexistence cluster).[7]
In February 2009, the tasks of updating the baseline document were allocated to four Technical Subgroups (TSGs): TSG1 for editorial tasks, TSG2 for the confirmed FFT and Wavelet PHYs and MACs, TSG3 to develop a potential ITU-T G.hn compatible PHY/MAC option (subsequently removed), and TSG4 for coexistence aspects.
On 24 July 2009, the working group approved the draft standard at a meeting in Tokyo.[8] In January 2010 the first draft standard was published.
In April 2010, the initial 30-day sponsor ballot on draft 3.0 yielded over 80% affirmative votes.[9][10][11] 857 comments were received.
In April 2010, IEEE announced that the Homeplug Powerline Alliance and the HD-PLC Alliance were developing a joint certification program for IEEE 1901's ISP coexistence protocol and that the program would be available in May 2010.[12]
In June 2010, the working group completed resolution of the sponsor ballot comments received on draft 3.0, and draft 4.0 was generated. With 93% affirmative votes, the group moved draft 4.0 to recirculation sponsor ballot. In September 2010, Draft 4.01 was submitted to the IEEE-SA Standards Board for consideration as an IEEE Standard at the 28–30 September board meeting. On 30 September, the standard was approved, and IEEE Std 1901-2010 was published 30 December 2010.[13]
Another trade group called the HomeGrid Forum was formed in 2008 to promote the incompatible ITU-T home networking standards known as G.hn.[14]
IEEE P1675 is another IEEE standard related to Broadband over Power Line. P1675 provides testing and verification standards for the hardware commonly used for Broadband over Power Line (BPL) installations (primarily couplers and enclosures) and provides standard installation methods to ensure compliance with applicable codes and standards.
IEEE P1775 ("Powerline Communication Equipment — Electromagnetic Compatibility Requirements — Testing and Measurement Methods") is an IEEE working group focused on PLC equipment, electromagnetic compatibility requirements, and testing and measurement methods.
IEEE 1905 is a working group for a "convergent digital home network".[15]
In Fall 2009, the idea for a new narrow band powerline communications standard, IEEE P1901.2, began taking shape.[16]
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