Broadband over power lines (BPL) is a method of power-line communication (PLC) that allows relatively high-speed digital data transmission over public electric power distribution wiring. BPL uses higher frequencies, a wider frequency range, and different technologies compared to other forms of power-line communications to provide high-rate communication over longer distances. BPL uses frequencies that are part of the radio spectrum allocated to over-the-air communication services; therefore, the prevention of interference to, and from, these services is a very important factor in designing BPL systems.
There are two main categories of BPL: in-house and access. In-house BPL is broadband access within a building or structure using the electric lines of the structure to provide the network infrastructure. Access BPL is the use of electrical transmission lines to deliver broadband to the home. Access BPL is considered a viable alternative to Cable or DSL to provide the 'final mile' of broadband to end users.[1]
BPL is based on PLC technology developed as far back as 1914 by the US telecommunications company AT&T.[2] In 1990s, BPL emerged as a means of leveraging the pervasiveness of the power grid to deliver high-speed broadband communications. The aim was to expand internet access to areas where traditional wired broadband solutions like DSL or cable were not readily available or economically viable.
In order to achieve high bandwidth levels, BPL operates at higher frequencies than traditional power line communications, typically in the range between 2 and 80 MHz.[3] The modulation techniques of BPL are Frequency Division Multiplexing (FDM) or Orthogonal Frequency Division Multiplexing (OFDM), which are both superior to Spread Spectrum or Narrowband for spectral efficiency, robustness against channel distortions, and the ability to adapt to channel changes.[4] Electricity companies have been bundling radio frequency on the same line as the electrical current to monitor the performance of their own power grids for years. There have been attempts to implement access BPL, or the provision of internet services to customers via the grid. The prospect of BPL was predicted in 2004 to possibly motivate DSL and cable operators to serve rural communities.[5]
More recently, decarbonization is leading to a significant increase in generation plants, storage devices, and consumers at lower voltage levels, causing capacity issues in distribution grids.[6] Traditional central control becomes not feasible for lower levels due to the vast number of units.[7] Energy utility companies such as E.ON, starts to adopt BPL as a key communication technology to enable real-time, high-speed decentralized control of the grid.[8]
Broadband Over Power Lines (BPL) works as specialized modems to convert data into signals and transmit alongside power lines, This process ensures consistent broadband connectivity through demodulation, data distribution, and interference mitigation.[3]
Power lines were not designed for data transmission, they were created to deliver AC power at 50 to 60Hz. If Broadband data is transmitted at different frequencies, then the data and electricity can travel in the same wire, however several obstacles have to be overcome to enable the high-speed and long-distance transmission of data on existing power lines.[citation needed]
Deployment of BPL has illustrated a number of fundamental challenges, 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. Switching power supplies often introduce noisy harmonics into the line. And unlike coaxial cable or twisted-pair, the wiring has no inherent noise rejection.
The second major issue is electromagnetic compatibility (EMC). The system was expected to use frequencies of 10 to 30 MHz in the high frequency (HF) range, used for decades by military, aeronautical, amateur radio, and shortwave broadcasters. Power lines are unshielded and will act as antennas for the signals they carry, and they will cause interference to high frequency radio communications and broadcasting. In 2007, the NATO Research and Technology Organization released a report which concluded that widespread deployment of BPL may have a "possible detrimental effect upon military HF radio communications."[9]
There have been many attempts worldwide to implement access BPL, all which have indicated that BPL is not viable as a means of delivering broadband Internet access. This is because of two problems: limited reach, and low bandwidth which do not come close to matching ADSL, Wi-Fi, and even 3G mobile. World major providers have either limited their BPL deployments to low-bandwidth connected equipment via smart grids, or ceased BPL operations altogether.
Australia saw trials of access BPL between 2004 and 2007; but no active access BPL deployments appear to remain there.[10]
In the UK, the BBC published the results of tests to detect interference from BPL installations.[11][12][13]
In the US, in October 2004, the US Federal Communications Commission adopted rules to facilitate the deployment of "Access BPL", the marketing term for Internet access service over power lines.
The technical rules are more liberal than those advanced by the US national amateur radio organization, the American Radio Relay League (ARRL), and other spectrum users, but include provisions that require BPL providers to investigate and correct any interference they cause.
One service was announced in 2004 for Ohio, Kentucky, and Indiana by Current Communications[14] but they left the BPL business in 2008.[15][16]
On August 3, 2006, FCC adopted a memorandum opinion and an order on broadband over power lines, giving the go-ahead to promote broadband service to all Americans.[17] The order rejected calls from aviation, business, commercial, amateur radio and other sectors of spectrum users to limit or prohibit deployment until further study was completed. FCC chief Kevin Martin said that BPL "holds great promise as a ubiquitous broadband solution that would offer a viable alternative to cable, digital subscriber line, fiber, and wireless broadband solutions".[18][19]
In the US, International Broadband Electric Communications (IBEC), which had an ambitious plan to provide access BPL in the US, ceased BPL operations in January 2012.[20][21]
On January 19, 2018, E.ON, the German multinational electric utility company serving approx. 48 million customers across different countries [*], decided to integrate BPL into their communication strategy, specifically for the smart metering communication infrastructure within the low voltage segment of their grid. E.ON chose Corinex as the solution provider for the initial two years of the deployment. The initial deployment was several ten thousand repeaters and headends, providing secure communication for a couple of hundred thousand households. Corinex GridValue energy management system based on the IBM Tivoli platform was selected to manage the network.[22]
Several standards are evolving for BPL technology including those of the IEEE, HomePlug Powerline Alliance (defunct), and PRIME Alliance.
There are many ways in which the communication signal may have error introduced into it. Interference, cross chatter, some active devices, and some passive devices all introduce noise or attenuation into the signal. When error becomes significant the devices controlled by the unreliable signal may fail, become inoperative, or operate in an undesirable fashion.