Networking 101: Broadband Over Powerline (BPL)
Look up at a utility pole and you will see several levels of wires, with the fiber and cable on the lower level, and the electrical higher up (for safety). Too often, implementation of new broadband is hampered by the costs, labor, restrictions and permits to run new wires onto these electrical poles. However, just about everyone in the developed world has a wire that already goes to their home via the electrical wire already on the pole.
We already know that electrical wiring can transmit data.
For under £100, you can get a set of Powerline adapters, and transmit data through the electrical wiring of your house. However the data transmission for Powerline networking does not go beyond the electrical meter, which is generally a good thing as it keeps the household’s data inherently secure.
However, there is a protocol for transmitting data through the existing electrical wiring on the utility poles which is called Broadband Over Powerline (BPL, with the alternate term Internet Over Powerline (IPL) to further differentiate it from Powerline technology). This technology also holds significant potential for the developing world, as it could potentially deliver broadband, with less infrastructure investment, through an already present power grid.
It also opens up new possibilities to connect a new generation of networked, plugged in devices, including clocks, television sets and kitchen appliances, as well as automated meter reading for electrical meters. Traditionally, the methods used to provide broadband internet access to a residence were to send it via a dedicated connection, via cable or fiber, and less commonly via the phone wires (DSL) or fixed wireless. With BPL, the broadband access is provided via the AC electrical connection, by bundling the data on a higher radio frequency (RF).
With the electrical energy and the data on separate frequencies, interference is minimized between the two so they can coexist without either compromising the other’s service. While all of this probably sounds quite useful, most likely you have not used BPL, nor do you have it as an option for your broadband access (After all who would not yearn to sign up for a ‘Double play’ option with their local electrical utility?). While electrical utilities are hardly known for their affordability, and holding the line on prices, at least the option of BPL would help the many consumers that have the option of only one ISP, or rural folks that need to turn to clearly second best options for internet access, such as fixed wireless, or satellite broadband.
BPL faces multiple impediments to ever really getting off the ground. There have been ongoing issues with the speeds and stability of jerry-rigging the current electrical grid, deployed long before the Internet was even conceived. High voltage wires are designed to transmit electrical energy over longer distances, but are not compatible with data transmission, relegating the data to medium and low voltage transmission lines.
Also the data signal degrades over distance, requiring repeater stations to maintain the data. Transformers, designed to reduce voltage, are another challenge as data cannot traverse them, and a CT coupler and a CT bridge are needed so the data has a pathway past the transformer. Other technological limitations include that transmitting data on the higher RF’s, while designed to avoid interference with electrical transmission, still ends up with quite a bit of it anyway, particularly for shortwave radio communications.
The final issue is that the longer it takes for BPL to come to market, other technologies, including wireless cellular LTE, and Gigabit fiber continue to evolve and improve, which translates to BPL needing to be even more robust to be able to remain competitive. BPL has found limited deployment, such as in Manassas, Virginia, where it served a little over 500 residences and businesses, and once prided itself as being the “most successful BPL deployment in the nation.” However, by July of 2010, this was shutdown due to a declining subscriber base, and running at a deficit to the city, although the reported quite affordable £25 monthly fee surely did not help the profitability. This was also applauded by amateur radio operators as the BPL was significantly interfering with their services.
BPL was also rolled out to rural America after technology giant IBM infused millions into Alabama based International Broadband Electric Communications, with a target of 340,000 homes. However, a few short years later, in 2012, the company shut the service down, citing damage from tornadoes, but critics believing it was due to the unsustainability of the technology. With such experiences, it looked like BPL was pretty much defunct in the US, while it did have some success internationally in such places as Romania, Moscow and Sweden.
Recently, AT&T has looked to overcome some of the limitations of BPL, dubbed AirGig. The data is sent wirelessly via plastic antennas between the towers using millimeter wireless radio waves, and is currently being done with Georgia Power, although there is no timeline for commercial deployment. The theory so far is that by not going directly through the electrical lines, the radio interference will be less, although, this also limits the use for scenarios of underground wiring.
BPL remains a useful technology that at least in the US, never really saw any degree of commercial success. Whether it will be reborn in a variation (albeit, a very distant cousin), such as AirGig remains to be seen. With many consumers looking to have a second or third provider in their neighborhood, let’s hope that BPL becomes an option in some iteration.
Feel free to discuss experiences with BPL, or the radio interference it produces, in the comments below.
This article was contributed by the DSLReports.com community.