Rapid growth in Western Europe will keep the HomePlug communication over power cable protocol level with the Multimedia Over Coax Alliance (MoCA), making these the two dominant wired standards for home networking, according to a forecast by ABI Research.
The survey predicts that each will be installed in 25 million households by 2014, but split geographically with MoCA dominating in North America and HomePlug in the key markets of Western Europe. The forecast is based first on the assumption that while WiFi may be the medium of choice for home networking, many houses will require some wired communications serving as a backbone to ensure good coverage and QoE (Quality of Experience). The next assumption is that home owners and service providers alike will want to avoid having to install new wires as far as possible to minimize costs and inconvenience. For this reason, MoCA is already popular in the U.S. where many homes have coax installed, while in Europe, where coax is much less prevalent, mains electricity wiring via mains sockets is the next best option.
At the same time, both MoCA and HomePlug are at similar levels of maturity in that there is no strong technical reason to prefer one or the other, according to ABI Research. The first significant shipments of the second versions of each, HomePlug AV2 and MoCA 2.0, are expected to occur during 2013, offering higher speeds up to 1Gb/s in theory, as well crucially as greater robustness under difficult line conditions.
HomePlug has had to make the greatest advance in bandwidth and robustness after criticisms that in practice it achieved well below the theoretical peak bit rate, and, in some cases, it was no more reliable than Wi-Fi, being subject to interference from other electrical devices. With AV2, the HomePlug consortium has introduced several important improvements to boost both performance and reliability.
The use of an additional 30MHz to 86MHz spectrum beyond that of the first version significantly increases throughput for multiple HD streams, improving peak data rates and average throughput. This is complemented by so called high efficiency PPDU (or packet on the wire) structure to reduce latency by handling packets more efficiently at high data rates. This brings HomePlug up to scratch for HD streaming and interactive services.
Multiple-Input Multiple-Output (MIMO) capabilities with Beam forming boosts performance further while enhancing robustness for HomePlug AV 2.0. It allows signals to be transmitted along any two wire pairs within three-wire configurations, which are quite common in both Europe and North America. While HomePlug AV 1.0 always transmits on the Line-Neutral pair, HomePlug AV2 can transmit on any two pairs formed by the Line, Neutral or Ground wires (i.e., Line-Neutral, Line-Ground or Neutral-Ground). This allows for significantly improved peak data rates and performance, as well as better signal coverage within the home.
Among other features, Immediate Repeating expands coverage by repeating the signal on paths with better SNR (Signal to Noise Ratio) characteristics. There are also various PHY (Physical Interface) improvements such as more robust Forward Error Correction (FEC), important for broadcast distribution, along with higher order modulation at 4096QAM, and higher code rates, that combine to improve throughput and robustness.
Taken together, these features have largely neutralized the arguments against HomePlug that used to be made by advocates for MOCA, which means that both will be deployed in significant numbers, even if, over time, penetration will level off as WiFi becomes yet more reliable. But, there will still be some deployment of MoCA in Europe, in areas where there is some coaxial cable installed. The biggest proponent of MoCA in Europe is cable operator Liberty Global, having chosen it as its wired back up to WiFi for its Horizon hybrid TV service, in preference to HomePlug.
It is not quite correct to regard HomePlug and MoCA as adversaries, as they both cooperated with DLNA (Digital Living Network Alliance) and the WiFi Alliance at the recent Consumer Electronics Show (CES) in Las Vegas to demonstrate how all four technologies could work together in the digital home. While few homes will have both Moca and Powerline, each of these will often be deployed alongside WiFi at the physical level, while DLNA provides higher level automatic device discovery, interoperability and secure content transmission. The wired networks, whether MoCA or HomePlug, will often serve as backbones between Wi-Fi routers and repeaters.
