The promise of powerband

Last Updated on September 16, 2007, 12:00 am
By Pauline Wangui

An emerging technology may be the newest heavy hitter in the competitive world of broadband Internet service.

Depending on who you talk to, though, it’s either a controversial idea that could jam radio communications or the next big thing for Internet access.

We’re talking ‘power-band’, ‘power-line Internet’ or broadband over power-lines (BPL). This is the use of power-line communications technology (PLC) to provide broadband Internet through ordinary power-lines. A computer or any other device would need only to plug a BPL modem into any outlet in an equipped building to have high-speed Internet access.

This technology promises to offer high-speed access through the most unlikely path — a common electrical outlet. With BPL, you can plug your computer into any electrical outlet in your home and instantly have access to high-speed Internet. Power-line communications technology can also be used to network home computers, peripherals or other networked consumer peripherals as the alternative ‘last mile’ platform.

Despite the proliferation of broadband technology in the last few years, there are still huge parts 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 cost of laying cable and building the necessary infrastructure to provide DSL or cable in rural areas is too great. But if broadband could be served through power-lines, there would be no need to build a new infrastructure.

Great promise

Anywhere there is electricity, there could be broadband. By slightly modifying the current power grids with specialised equipment, the BPL developers could partner with power companies and Internet service providers to bring broadband to everyone with access to electricity.

By just providing high-speed data transmission between all of the electrical plugs in a house or building there is the potential to network all kinds of common appliances in a household. If your alarm clock, light switch and coffee maker could talk each other via a high-speed connection, mornings might look a lot more different.

The idea of using alternating current (AC) power to transfer data is not new. Bundling radio-frequency (RF) energy on the same line with an electric current, data can be transmitted without the need for a separate data line.

BPL seems to offer benefits relative to regular cable or DSL connections. For instance, the extensive infrastructure already available would allow people in remote rural locations to have access to Internet with relatively little equipment investment by the utility. Also, such ubiquitous availability would make it very much easier to motivate telecommunications and cable operators to move quickly to serve rural communities.

BPL holds great promise as a ubiquitous broadband solution that would offer a viable alternative to cable; digital subscriber line, fibre and wireless broadband solutions and it should be one of the local ICT sector’s top priorities.

Like telephone companies, power companies do have lines strung all over the world. The difference is that power companies have power-lines in a lot more places than telephone companies have their infrastructure. This makes power-lines an obvious vehicle for providing Internet to places where these infrastructures have not reached like in the rural areas.

Since BPL signals cannot readily pass through transformers repeaters would have to be attached to the transformers. In the US, it is common to see small transformer hung from a utility pole to service a single house or a small number of houses. Broadband over power-lines has developed faster in Europe than in other parts of the world. It is even more common for a somewhat larger transformer to service ten or 100 houses in Europe. Delivering such BPL over the power grid of a typical Kenyan city might require many more repeaters than would be required in a comparable European city.

BPL can also be used as a backhaul for wireless communications, for instance by hanging WiFi 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. In the near future, BPL might also be used as a backhaul for WiMAX networks. Power-line carrier apparatus may also be useful as a backup channel or for very simple low-cost installations.

Like any other technology, BPL has a number of complex issues, the primary one being that power-lines are inherently a very noisy environment. Every time a device turns on or off, it introduces a pop or click into the line. Energy-saving devices often introduce noise into the line. The system must be designed to deal with these natural signalling disruptions and work around them. Universal standards are still being developed to allow interoperability between equipment from different manufacturers and co-existence of multiple power-line systems within the same environment. The advancement of BPL is moving forward as it waits for standards and logistics to be decided by world’s regulating bodies.

BPL can support many applications

Recently, power and telecommunications companies have started tests of the BPL technology. South Africa has already trialled the technology and is offering service in the suburbs of Pretoria with plans to extend coverage to other areas.

In the US the city of Manassas began the first wide-scale deployment of BPL service offering 10Mbps service for under $30 (about Sh2,000) per month to its city residents. In January 2006, a PLC trial was introduced by the Ministry of Communications and Information Technology in Romania offering phone and broadband internet access.

The technology was introduced to 50 households. If successful, it is hoped that the technology will be extended to other rural areas throughout Romania.

Successful pilots for the Electricity Company of Ghana (ECG) have been carried out since 2005. These combines fibre, radio link, Wi-fi and PLC to provide broadband Internet access and telephony, It showcases the inter-operability of the PLC technology and the company’s expertise in emerging market design and deployment.

There are many applications that can be supported by BPL. One natural application of power-line communication is the control and telemetry of electrical equipment such as meters, switches, heaters and domestic appliances.

Control and telemetry applications include automatic meter reading, load management, load profile recording, credit control, pre-payment, remote connection, fraud detection and network management, and could be extended to include gas and water.

These could also include street lighting control, remote metering and billing, customer specific tariff optimization, contract management, expense estimation and gas applications safety.

There are also many specialised niche applications which use the mains supply within the home as a convenient data link for telemetry. For example, in the UK and Europe a TV audience monitoring system uses power-line communications as a convenient data path between devices that monitor TV viewing activity in different rooms in a home and a data concentrator which is connected to a telephone modem. Power-line communication is used for transmitting radio programmes over power-lines or over telephone.

Power-line technology also enables in-vehicle network communication of Data, Voice, Music and Video signals by digital means. Advanced digital communication techniques tailored to overcome hostile and noisy environment are implemented in a small size silicon device.