05-07-2012, 12:40 PM
Broadband over Power Lines
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Introduction
The National Communications System (NCS) was established through a Presidential Memorandum signed by President John Kennedy on August 21, 1963. The memorandum assigned the NCS the responsibility of providing necessary communications for the Federal Government under national emergency conditions by linking together, improving, and expanding the communication capabilities of the various agencies.
In April 1984, President Ronald Reagan signed Executive Order (E.O.) 12472, Assignment of National Security and Emergency Preparedness (NS/EP) Telecommunications Functions,ii which broadened the mission and focus. Since that time, the NCS has been assisting the President and the Executive Office of the President (EOP) in exercising wartime and non-wartime emergency telecommunications and in coordinating the planning for, and provisioning of, NS/EP communications for the Federal Government under all circumstances. In this regard, the Office of the Manager, the NCS (OMNCS) continually seeks to improve the Federal Government's ability to respond to the telecommunications requirements to support national security and emergency situations. Among these responsibilities, the NCS seeks to ensure that a national telecommunications infrastructure is developed that “is capable of satisfying priority telecommunications requirements under all circumstances.” The OMNCS is the appropriate body to communicate NS/EP requirements to standards bodies and participate in related standards activities.
As part of this mission, the NCS Technology and Programs Division (N2) identifies new technologies that enhance NS/EP communications capabilities and ensures key NS/EP features, such as priority, interoperability, reliability, emerging standards support, availability, and security. In concert with this approach, the N2 manages the Federal Telecommunications Standards Program (FTSC). Additionally, the N2 division directs efforts in both NS/EP management and applications services.
On March 1, 2003, President George W. Bush transferred the NCS from the Department of Defense (after nearly 40 years of serving as the NCS’s Executive Agent) to the Department of Homeland Security (DHS). The NCS was one of 22 Federal agencies transferred to the Department in accordance with Executive Order(E.O.) 13286.iii A revised Executive Order 12472 reflects the changes of E.O. 13286. Today, the NCS is part of the Office is Cyber Security and Communications (CS&C). CS&C is an element of the DHS National Protection and Programs Directorate headed by the Under Secretary who also serves as the National Communications Manager. This Technical Information Bulletin (TIB) examines Broadband over Power Lines (BPL). It incorporates by reference the FCC 04-245 Report and Order of October 14, 2004 titled: “Amendment of Part 15 Regarding New Requirements and Measurement Guidelines For Access Broadband Over Power Line Systems Carrier Current Systems, Including Broadband Over Power Line Systems” and the updated revised FCC Part 15 regulations released on September 19, 2005.
Goals
The goals of this TIB are to:
• Present a brief introduction to BPL technology
• Identify the potential benefits of BPL for NS/EP applications in support of Critical Infrastructure Protection (CIP) requirements
• Describe technical issues related to BPL for NS/EP
• Identify areas for further development of the technology that would enhance the government’s NS/EP mission performance capabilities
This TIB is intended to provide technical, administrative, and other information pertaining to BPL technology for consideration by the agency members of the NCS. BPL technology has a variety of names around the world including: Power Line Telecommunications (PLT), Power Line Communications (PLC) and others. For consistency, even when material from foreign countries is referenced, BPL is applied throughout this TIB.
1.2 Background and Introduction Subscribers per 100 population
According to the Institute for Electronic and Electrical Engineers (IEEE)iv and the International Telecommunications Union (ITU) the United States is lagging behind other countries in the deployment of broadband telecommunications networks. In December 2005 the ITU documented (see Figure 1) that among the top 20 worldwide economies, US broadband deployment ranks in the bottom 20%. In the US, broadband services to the home are largely provided by cable modems and digital subscriber loop (DSL) services. These broadband services operate mostly in the range of 1 - 6 megabits per second (Mb/s) downstream to the user, but only 750 kilobits per second (Kb/s) or less upstream. In most of South Korea, residents have access to 50 - 100 Mb/s, which in many cases is symmetrical. South Korea achieved this infrastructure through a government policy supporting deregulation, competition and
investment.
Japan also adopted competitive policies leading to widespread 50- to 100-Mb/s symmetrical operations with low prices.v Japan is rapidly deploying symmetric optical fiber networks connected directly to the home. Gigabit per second (Gb/s) availability to Japanese homes began in 2005.
In April of 2003 the FCC issued a Notice of Inquiry (NOI) titled: “Inquiry Regarding Carrier Current Systems, including Broadband over Power Line Systems.”vi In the notice the FCC identified BPL as a new type of carrier current system that operates on an unlicensed basis under Part 15 of the FCC’s rules. BPL systems use the existing electrical power lines as a transmission medium to provide high-speed telecommunications capabilities by coupling Radio Frequency (RF) energy onto the power line. In the NOI, the FCC proposed that “because power lines reach virtually every community in the country, BPL could play an important role in providing additional competition in the offering of broadband infrastructure to the American home and consumers.” Additionally, the NOI offered that “BPL could bring internet and high-speed broadband access to rural and underserved areas, which often are difficult to serve due to the high costs associated with upgrading existing infrastructure and interconnecting communication nodes with new technologies.” Thus the FCC has identified that BPL has the potential to become an effective means for “last-mile delivery of broadband services and may offer a competitive alternative to digital subscriber line (DSL), cable modem services, satellite, Wireless Fidelity (WiFi™), fiber optic, and other high speed internet access technologies.” The FCC received approximately 5,000 comments from the NOI and subsequently on October 14, 2004 issued “Amendment of Part 15 Regarding New Requirements and Measurement Guidelines For Access Broadband Over Power Line Systems Carrier Current Systems, Including Broadband Over Power Line Systems.vii” This ruling placed the United States under the most liberal BPL regulatory environment found anywhere in order to encourage the rapid deployment of BPL systems.
The capability of using the electrical supply networks for telecommunications has been known since the 1800s. In the US, during the 1920s, AT&T was awarded several patents for these technologies. During the 1930s, ripple carrier signaling (RCS) began to operate on power lines. RCS used the frequency range 125 Hz - 3 KHz with amplitude shift keying (ASK) modulation. RCS provided data rates in the order of a few bits per second but this was sufficient for the load management and automatic reconfiguration of power distribution networks that were the most important tasks performed using RCS. In the 1950s, power utilities were using low frequencies (<1 kHz) to send control messages to equipment on the power grid. By the 1980s, bi-directional communications in the 5 – 500 kHz band were being used. Following these narrowband, low-data-rate BPL applications, broadband BPL started to develop and today commercialized products for LAN applications and Internet access are becoming more widely available.
BPL is an interdisciplinary topic that includes: antennas and propagation, power engineering, electromagnetic compatibility, telecommunications, and others. The FCC categorizes the new low-power unlicensed BPL systems into two general types: (1) Access BPL systems that couple RF energy onto medium and low voltage power lines, and (2) In-home BPL networks, which use electrical outlets available within a building or home to provision a LAN.
BPL Overview
In the past few years, the availability of much faster digital signal-processing capabilities and the development of sophisticated modulation, encoding, and error correction schemes have allowed the introduction of new, low-power designs for carrier current devices. These new designs can overcome earlier technical bandwidth limitations caused by the inherent noise and impedance mismatches that are common on commercial power lines. The new designs include the use of spread spectrum or multiple carrier techniques that employ highly adaptive algorithms to effectively counter the noise on the line. They also include the use of “turbo code” (TC) techniques such as concatenated Reed-Solomon Forward Error Correction (FEC) and convolutional coding employing the Viterbi algorithm, which can provide decibel (dB) gains that approach Shannon’s famous channel capacity law1.
BPL Access and In-home technologies currently suffer from the absence of recognized international and, in most cases, national standards. Consequently, there is relatively little detailed public technical information available on BPL systems, reflecting their proprietary state. BPL manufacturers today maintain a secretive posture with respect to the technical details of their equipment. Although the US does follow the electrical power standards set by the International Electrotechnical Committee (IEC), each power company has wide flexibility in how their own transmission facilities are implemented. Thus it is difficult to render accurate generalizations about even the underlying power structure that facilitates BPL. This will improve over the next few years after a number of current standardization efforts, discussed later, are concluded.
Power Line Infrastructure
BPL is designed to take advantage of the in-place electrical power grid, which varies among countries around the world. In the United States, the three-phase alternating current (A/C) electrical power grid is a three-tiered hierarchical system that is comprised of: (1) high voltage (HV); (2) medium voltage (MV); and (3) low voltage (LV) transmission lines. HV lines connect electricity generation stations to distribution stations. HV lines carry in the order of hundreds of kilovolts over distances that are tens of kilometers. MV lines connect the distribution stations to pole-mounted transformers. MV lines typically carry in the order of double-digit kilovolts over distances of a few kilometers. LV lines connect pole-mounted transformers to individual businesses and homes. LV lines carry only a few hundred volts over distances of a few hundred meters. In the US, each transformer supports only a few (e.g., 1-8) customers.
[attachment=26825]
Introduction
The National Communications System (NCS) was established through a Presidential Memorandum signed by President John Kennedy on August 21, 1963. The memorandum assigned the NCS the responsibility of providing necessary communications for the Federal Government under national emergency conditions by linking together, improving, and expanding the communication capabilities of the various agencies.
In April 1984, President Ronald Reagan signed Executive Order (E.O.) 12472, Assignment of National Security and Emergency Preparedness (NS/EP) Telecommunications Functions,ii which broadened the mission and focus. Since that time, the NCS has been assisting the President and the Executive Office of the President (EOP) in exercising wartime and non-wartime emergency telecommunications and in coordinating the planning for, and provisioning of, NS/EP communications for the Federal Government under all circumstances. In this regard, the Office of the Manager, the NCS (OMNCS) continually seeks to improve the Federal Government's ability to respond to the telecommunications requirements to support national security and emergency situations. Among these responsibilities, the NCS seeks to ensure that a national telecommunications infrastructure is developed that “is capable of satisfying priority telecommunications requirements under all circumstances.” The OMNCS is the appropriate body to communicate NS/EP requirements to standards bodies and participate in related standards activities.
As part of this mission, the NCS Technology and Programs Division (N2) identifies new technologies that enhance NS/EP communications capabilities and ensures key NS/EP features, such as priority, interoperability, reliability, emerging standards support, availability, and security. In concert with this approach, the N2 manages the Federal Telecommunications Standards Program (FTSC). Additionally, the N2 division directs efforts in both NS/EP management and applications services.
On March 1, 2003, President George W. Bush transferred the NCS from the Department of Defense (after nearly 40 years of serving as the NCS’s Executive Agent) to the Department of Homeland Security (DHS). The NCS was one of 22 Federal agencies transferred to the Department in accordance with Executive Order(E.O.) 13286.iii A revised Executive Order 12472 reflects the changes of E.O. 13286. Today, the NCS is part of the Office is Cyber Security and Communications (CS&C). CS&C is an element of the DHS National Protection and Programs Directorate headed by the Under Secretary who also serves as the National Communications Manager. This Technical Information Bulletin (TIB) examines Broadband over Power Lines (BPL). It incorporates by reference the FCC 04-245 Report and Order of October 14, 2004 titled: “Amendment of Part 15 Regarding New Requirements and Measurement Guidelines For Access Broadband Over Power Line Systems Carrier Current Systems, Including Broadband Over Power Line Systems” and the updated revised FCC Part 15 regulations released on September 19, 2005.
Goals
The goals of this TIB are to:
• Present a brief introduction to BPL technology
• Identify the potential benefits of BPL for NS/EP applications in support of Critical Infrastructure Protection (CIP) requirements
• Describe technical issues related to BPL for NS/EP
• Identify areas for further development of the technology that would enhance the government’s NS/EP mission performance capabilities
This TIB is intended to provide technical, administrative, and other information pertaining to BPL technology for consideration by the agency members of the NCS. BPL technology has a variety of names around the world including: Power Line Telecommunications (PLT), Power Line Communications (PLC) and others. For consistency, even when material from foreign countries is referenced, BPL is applied throughout this TIB.
1.2 Background and Introduction Subscribers per 100 population
According to the Institute for Electronic and Electrical Engineers (IEEE)iv and the International Telecommunications Union (ITU) the United States is lagging behind other countries in the deployment of broadband telecommunications networks. In December 2005 the ITU documented (see Figure 1) that among the top 20 worldwide economies, US broadband deployment ranks in the bottom 20%. In the US, broadband services to the home are largely provided by cable modems and digital subscriber loop (DSL) services. These broadband services operate mostly in the range of 1 - 6 megabits per second (Mb/s) downstream to the user, but only 750 kilobits per second (Kb/s) or less upstream. In most of South Korea, residents have access to 50 - 100 Mb/s, which in many cases is symmetrical. South Korea achieved this infrastructure through a government policy supporting deregulation, competition and
investment.
Japan also adopted competitive policies leading to widespread 50- to 100-Mb/s symmetrical operations with low prices.v Japan is rapidly deploying symmetric optical fiber networks connected directly to the home. Gigabit per second (Gb/s) availability to Japanese homes began in 2005.
In April of 2003 the FCC issued a Notice of Inquiry (NOI) titled: “Inquiry Regarding Carrier Current Systems, including Broadband over Power Line Systems.”vi In the notice the FCC identified BPL as a new type of carrier current system that operates on an unlicensed basis under Part 15 of the FCC’s rules. BPL systems use the existing electrical power lines as a transmission medium to provide high-speed telecommunications capabilities by coupling Radio Frequency (RF) energy onto the power line. In the NOI, the FCC proposed that “because power lines reach virtually every community in the country, BPL could play an important role in providing additional competition in the offering of broadband infrastructure to the American home and consumers.” Additionally, the NOI offered that “BPL could bring internet and high-speed broadband access to rural and underserved areas, which often are difficult to serve due to the high costs associated with upgrading existing infrastructure and interconnecting communication nodes with new technologies.” Thus the FCC has identified that BPL has the potential to become an effective means for “last-mile delivery of broadband services and may offer a competitive alternative to digital subscriber line (DSL), cable modem services, satellite, Wireless Fidelity (WiFi™), fiber optic, and other high speed internet access technologies.” The FCC received approximately 5,000 comments from the NOI and subsequently on October 14, 2004 issued “Amendment of Part 15 Regarding New Requirements and Measurement Guidelines For Access Broadband Over Power Line Systems Carrier Current Systems, Including Broadband Over Power Line Systems.vii” This ruling placed the United States under the most liberal BPL regulatory environment found anywhere in order to encourage the rapid deployment of BPL systems.
The capability of using the electrical supply networks for telecommunications has been known since the 1800s. In the US, during the 1920s, AT&T was awarded several patents for these technologies. During the 1930s, ripple carrier signaling (RCS) began to operate on power lines. RCS used the frequency range 125 Hz - 3 KHz with amplitude shift keying (ASK) modulation. RCS provided data rates in the order of a few bits per second but this was sufficient for the load management and automatic reconfiguration of power distribution networks that were the most important tasks performed using RCS. In the 1950s, power utilities were using low frequencies (<1 kHz) to send control messages to equipment on the power grid. By the 1980s, bi-directional communications in the 5 – 500 kHz band were being used. Following these narrowband, low-data-rate BPL applications, broadband BPL started to develop and today commercialized products for LAN applications and Internet access are becoming more widely available.
BPL is an interdisciplinary topic that includes: antennas and propagation, power engineering, electromagnetic compatibility, telecommunications, and others. The FCC categorizes the new low-power unlicensed BPL systems into two general types: (1) Access BPL systems that couple RF energy onto medium and low voltage power lines, and (2) In-home BPL networks, which use electrical outlets available within a building or home to provision a LAN.
BPL Overview
In the past few years, the availability of much faster digital signal-processing capabilities and the development of sophisticated modulation, encoding, and error correction schemes have allowed the introduction of new, low-power designs for carrier current devices. These new designs can overcome earlier technical bandwidth limitations caused by the inherent noise and impedance mismatches that are common on commercial power lines. The new designs include the use of spread spectrum or multiple carrier techniques that employ highly adaptive algorithms to effectively counter the noise on the line. They also include the use of “turbo code” (TC) techniques such as concatenated Reed-Solomon Forward Error Correction (FEC) and convolutional coding employing the Viterbi algorithm, which can provide decibel (dB) gains that approach Shannon’s famous channel capacity law1.
BPL Access and In-home technologies currently suffer from the absence of recognized international and, in most cases, national standards. Consequently, there is relatively little detailed public technical information available on BPL systems, reflecting their proprietary state. BPL manufacturers today maintain a secretive posture with respect to the technical details of their equipment. Although the US does follow the electrical power standards set by the International Electrotechnical Committee (IEC), each power company has wide flexibility in how their own transmission facilities are implemented. Thus it is difficult to render accurate generalizations about even the underlying power structure that facilitates BPL. This will improve over the next few years after a number of current standardization efforts, discussed later, are concluded.
Power Line Infrastructure
BPL is designed to take advantage of the in-place electrical power grid, which varies among countries around the world. In the United States, the three-phase alternating current (A/C) electrical power grid is a three-tiered hierarchical system that is comprised of: (1) high voltage (HV); (2) medium voltage (MV); and (3) low voltage (LV) transmission lines. HV lines connect electricity generation stations to distribution stations. HV lines carry in the order of hundreds of kilovolts over distances that are tens of kilometers. MV lines connect the distribution stations to pole-mounted transformers. MV lines typically carry in the order of double-digit kilovolts over distances of a few kilometers. LV lines connect pole-mounted transformers to individual businesses and homes. LV lines carry only a few hundred volts over distances of a few hundred meters. In the US, each transformer supports only a few (e.g., 1-8) customers.