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Broadband Over Power Lines

Lee Layton, P.E.


Course Outline

This course begins with an in-depth review of all current technologies to deliver broadband to the home including DSL, CATV, wireless and satellite services.  The second chapter explains how BPL works and the different architectures used to deliver BPL.  The different business models for BPL are discussed as well as the regulatory hurdles that BPL must overcome.

This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of the course materials.

Learning Objective

After taking this course you should:

Intended Audience

This course is intended anyone who wants to understand the potential for BPL to provide another alternative for internet service.

Benefit to Attendees

This course gives a good overview of the current internet services available and their limitations and explains how BPL might be used to provide more competition for the delivery of internet service.

Course Introduction

Despite the spread of broadband technology in the last few years, there are significant areas of the world that don't have access to high-speed Internet. When weighed against the relatively small number of customers Internet providers would gain, the incremental expenditures of building the necessary infrastructure to provide DSL or cable in many areas, especially rural, is too great. But if broadband could be served through power lines, there would be no need to build a new infrastructure. Anywhere there is electricity there could be broadband.

Broadband over powerlines (BPL) allows customers to get high-speed internet connections through their electrical outlets. Users can plug a power line modem into an electric socket anywhere in their home, without requiring any special installation or wiring. Broadband over power lines (BPL) is the use of PLC technology to provide broadband Internet access through ordinary power lines. A computer would need only to plug a BPL modem into any outlet in an equipped building to have high-speed Internet access.

BPL may offer benefits over regular cable or DSL connections: the extensive infrastructure already available allows people in remote locations to access the Internet with relatively little equipment investment by the utility. Also, such ubiquitous availability would make it much easier to connect other electronics, such as televisions or sound systems.

Deployment of BPL has illustrated a number of fundamental challenges, the primary one being that power lines are inherently a very noisy environment. The system must be designed to deal with these natural signaling disruptions and work around them.

Broadband over power lines has developed faster in Europe than in the United States due to a historical difference in power system design philosophies. Power distribution uses step-down transformers to reduce the voltage for use by customers. But BPL signals cannot readily pass through transformers, as their high inductance makes them act as low-pass filters, blocking high-frequency signals. So, repeaters must be attached to the transformers. In the U.S., it is common for a small transformer installed from a utility pole to service a single house or a small number of houses. In Europe, it is more common for a somewhat larger transformer to service 10 or 100 houses. For delivering power to customers, this difference in design makes little difference for power distribution. But for delivering BPL over the power grid in a typical U.S. city requires an order of magnitude more repeaters than in a comparable European city. On the other hand, since bandwidth to the transformer is limited, this can increase the speed at which each household can connect, due to fewer people sharing the same line. One possible solution is to use BPL as the backhaul for wireless communications, for instance by installing Wi-Fi access points or cell phone base stations on utility poles, thus allowing end-users within a certain range to connect with equipment they already have.
 
The second major issue is signal strength and operating frequency. The system is expected to use frequencies of 10 to 30 MHz, which has been used for many decades by amateur radio operators, as well as international shortwave broadcasters and a variety of communications systems. Power lines are unshielded and will act as antennas for the signals they carry, and have the potential to interfere with shortwave radio communications.

Course Content

This course content is in the following PDF document:

Broadband Over Power Lines

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Course Summary

Deploying broadband over power lines holds promise has an alternative, or “third wire” into millions of home within the U.S.  Tests have shown that 1) BPL does work and can deliver internet over power lines and 2) BPL system cause interference that must be managed.  The interest in BPL has waned some since the turn of the century, but companies are still evaluating how BPL might successfully be deployed. Numerous technology and regulatory hurdles must be overcome to make this a viable alternative to DSL, CATV, and satellite delivery of broadband. 

Quiz

Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.

DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.