HomePlug AC Networking
We connected with HomePlug before the open of the CES Expo and were able to get a few question and answer sessions regarding their new technology which allows in-home networking over AC lines as well as Broadband over Powel Lines (BPL).
What are HomePlug AV's speed, features and capabilities?
HomePlug AV was designed to support the high-bandwidth and low-latency demands of several simultaneous streams of HDTV and VoIP, made concurrently available in over 90% of power outlets in a home. The target applications are in-home distribution of audio-video in home-theater and data-networking environments. For this reason, in the given frequency range, HomePlug AV has pushed Shannon's Law to its limit and provides a 200Mbps class service at the PHY layer. After overhead considerations, the MAC layer will support over 100Mbps.
Which frequency range is HomePlug AV using? Does HomePlug have any plans to use higher frequencies (e.g. above 30 MHz) and if not, why not?
HomePlug AV will use frequencies in the range of 2 to 28 MHz. The alliance does not currently have any plans to use frequencies above 30 MHz, but there is a possibility for expanding this range to higher frequencies depending on governmental regulations in the future.
What underlying technologies does HomePlug AV employ?
HomePlug AV uses an OFDM PHY with advanced FEC, channel estimation and adaptation. The MAC incorporates both scheduled access (TDMA) with QoS guarantees and contention access (CSMA), with reliable delivery through fast ARQ. HomePlug AV supports TDMA and FDMA for purposes of Broadband Over Powerline (BPL) co-existence. The HomePlug AV protocol stack supports a variety of upper layer protocols native to HomePlug AV, 802.3, IP and UPNP.
How does HomePlug AV support both In-home and BPL uses on the same wire?
HomePlug AV has a mechanism to detect the existence of "neighbor networks," which includes BPL users. This mechanism is required so that in-home-only HomePlug AV users in homes and apartments that are sharing the same physical wire (off of a common transformer) do not interfere with each other - independent of whether BPL exists on the line or not. In other words, the need for bandwidth sharing exists inherently within HomePlug AV itself, and the bandwidth management solutions needed for In-home HomePlug AV applications can easily be extended to HomePlug BPL.
With that said, the HomePlug alliance recognizes that the market requirements of BPL may differ from those of HomePlug AV. Therefore, policies will need to be established on how best to share available resources between HomePlug AV and BPL. To a large degree, specific deployment scenarios, service architectures and possibly government regulations will drive this policy determination. The goal of HomePlug AV is to create a technology specification that can support those policy determinations, whatever they may be.
For more information, please visit http://www.homeplug.org .