Junior Isles

November saw Consolidated Edison (Con Ed), one of the US’ largest investor-owned utilities, carry out alpha-phase testing of powerline carrier telecommunications (PLT). The testing is a significant milestone in the utility’s strategy to offer more services and will also be another crucial step for a technology which has had its ups and downs over the last three years.

This latest test is being conducted in New York under the terms of a joint Ambient Corporation/ConEd pilot project announced on August 16 last year that will hopefully see the future commercial deployment of Ambient’s proprietary technology over Con Ed’s electric lines.

Partner approach

Ambient Corporation is a publicly traded company that operates technology companies in the US and Israel, focusing on PLT, telephony-related product offerings, Internet and e-commerce for a variety of consumer applications. The company has developed its own proprietary technology that facilitates the transfer of Internet and high speed data through ordinary electric power lines. According to Ambient, the technology is designed to enable utilities to partner with Ambient in creating a basket of utility and consumer services.

Ambient is taking a partnership approach in its effort to commercialize this technology. It has announced partnerships with Con Ed and Sumitomo Electric Industries. Con Ed has come in in a big way, having a member on Ambient’s advisory Board. Commenting on their relationship, Mark Isaacson, CEO of Ambient Corp. said: “Our relationship with Con Ed began about ten months ago. They have a lot of enthusiasm. They are also a perfect type of utility, based on the density of population in New York, who really want to serve their customers. Their learning centre in Queens also allows us to work in an excellent simulated environment.”

Such moves into PLT are not the first. Norweb/Nortel began developing the technology three years ago (see PEI January 1998) before the plug was pulled on the project. However, Isaacson believes it will now succeed because of three major reasons: “Firstly, the technology is much better today than it has ever been; secondly we have the right partners in place on the utility side and the technology side; and thirdly, we are taking a step-by-step approach. Norweb were looking to do large scale pilots before they were ready.”

Technology with potential

In a typical PLT system, there are three critical pieces of equipment in the system (in addition to the modem): the bypass transformer device, also known as a coupler which according to Isaacson solves the “last mile”; the home gateway which connects into the premises; and the head-end router server device.

Schematically the data starts on a backbone which could be fibre running along the utility’s network, it then travels through the filter and router to the neighbourhood. Data from the router flows to a modem where it is modulated and fed to a medium voltage coupler. This places the modulated data onto the medium voltage line.

There is a coupler at each distribution transformer on the line which removes the modulated signal from the line and places it on what Ambient calls a pole-top box. This box regenerates the bits; re-modulates them and puts the data on the low voltage access line into each premise which has a home gateway at the entrance.

One drawback with PLT is the possibility of interference by noise in buildings which can be caused by things such as fluorescent lights or drills. However, Ambient explains that because its technology operates at very high frequencies (MHz) any noise generated has only a residual effect. Its spread spectrum technology also eliminates narrow band noise.

Dr. Yehuda Cern, Ambient’s chief engineer also noted: “The distribution transformers tend to block high frequencies completely and this is why until now, medium voltage has not been a viable channel. But by the same token, those distribution transformers block noise from the low voltage network from getting back onto the medium voltage network. This leaves the medium voltage network as a very quiet medium which in turn facilitates higher data rates.”

Distances and the amount interference that can be tolerated on the lines are at the moment limited. The furthest Ambient’s technology has been able to achieve for sharing services has been 120 m. On a typical low voltage feed, Ambient is hoping to achieve a minimum distance of about 400 m. This minimum would be more than sufficient for the US or Japanese market where distances from the distribution transformer to the home are typically 50-100 m, but much greater distances will be needed for the medium voltage network.

Yehuda added: “It’s not just an issue of raw distance. It is also about the amount of branching and the topology of the network which tends to cause signal weakening.”


One reason cited by Nortel for it stopping work on PLT was competition from other cable technologies such as ADSL (asynchronous digital subscriber line).

A major point of comparison has been the issue of speed. According to Isaacson, at the moment we are seeing raw speeds in the high 20 Mbit/s range and throughputs approaching 10 Mbit/s but he put the speed issue into context: “Speed should be measured in real terms instead of how marketing people measure speed. For example, if you consider speed on a cable modem you may be talking about a head-end which serves 10 000 homes. You may have 100 Mbits/s but it will be diluted by everybody on it at the same time.

“If everyone is downloading files at the same time you are looking at very little speed. It is better to have lower speeds which are not diluted by usage or distances i.e. it’s better to have 1 Mbit/s all to yourself than 10 000 Mbit/s shared between 110 000 people.”

Taking this approach, Isaacson believes PLT is faster or at least as fast as any competing technology with the exception of specialized systems such as T1. ADSL is also an asymmetrical service i.e. the upload speed is limited compared to the download speed. PLT is symmetrical with the same upload and download speeds.

Isaacson said: “Multi-megabit throughput, which is also scalable i.e. increasing in distance and speed under increasing interference as well as services, is the platform. We will comfortably deliver 5-10 Mbit/s on a throughput basis by the time we go commercial.”

Isaacson also believes its costs will be comparable to other broadband services with a bigger basket of services. He also believes that the reliability of the power grid is better than cable, at least in the US, and that it will be less prone to hiccups than telephone.

Test programme

But it is early days yet. The Con Ed test was a successful alpha test (i.e. point-to-point), which demonstrated proof of concept. It was conducted at Con Ed’s Learning Centre Facility in Queens, New York, on November 20, 2000.

In this test, Ambient’s PLT technology showed its capabilities for streaming video, video conferencing and Internet connectivity over standard electric lines.

Alpha testing will continue for the next 2-4 months during which Ambient will be looking to increase distances; maintain operation under increasing levels of interference; and achieve higher frequencies. Technology is also being incorporated to enable the system to “learn” how to keep its signal strong over long distances.

Certainly the technology is improving continually. The company said that distances achieved over the last month have increased significantly. In another alpha test conducted in Japan, Ambient achieved distances 6-9 times greater than those achieved with Con Ed and under greater interference conditions.

Another test was run on every floor in an eight floor high rise building in Hong Kong which, as Isaacson put it: “ran with phenomenal frequency and data readings”. He added: “We were running upwards of 28 Mbits/s in terms of raw speed. On frequency reading and data transfer we were able to achieve distances of about 180 m and about 120 m for services (streaming video, internet etc.).”

At the next beta test level, Ambient will be continuing with the same work but over a point-multi point network as opposed to a point-to-point network.

The next phase of testing will then involve, first 5-10 homes, increasing to 100 homes across a wide area of a utility’s territory. “These homes will be miles apart so that we are able to run them over the same network. We should then be able to go from these tests to commercialization in say 18 months from now.”

Commenting on the results, Isaacson said: “The promising results should send a clear message to utilities, consumers and the financial community, that PLT technology is here, it is real, and full deployment is just a question of time.”

Market penetration

While time will see the technology mature, there will still be the task of capturing customers. In areas where cable is prolific, there will be a market challenge in trying to sway the customer to make the switch. Isaacson noted however: “We will feel we have the best argument. Utilities have a wonderful platform. They have a well developed customer base and will be able to offer many services, not just data and telephone.”

Ambient is expecting global takeup of its technology. “Our first opportunity will be in the US, and then in Europe and Asia. Most of our testing is in the US and Asia The European arena is crowded at the moment.” Indeed, companies like M@inNet.net Communications have delivered orders for its technology in Germany, Italy, Spain, France and Sweden.

This increasing level of activity from different companies will improve the industry’s overall knowledge of what needs to be done to achieve commercial success.

As Isaacson concluded: “Every electrical network has surprises and every utility has surprises. It will be a case of getting the technology out there and operating in as many different environments as possible.”