Introduction to PLC

1. Power Line Communication
Submitted to:
Prof. Dr.- Ing. Ulrich Trick
Fachhochschule Frankfurt am Main
University of Applied Sciences
Forschungsgruppe für Telekommunikationsnetze
Submitted by:
Piyush Chand
M.Eng.(I.T.) Student
Fachhochschule Frankfurt am Main
University of Applied Sciences
Forschungsgruppe für Telekommunikationsnetze
Course: Mobile Computing

2. CONTENT
• Introduction
• Power Line Communication System
• Types of PLC Architecture
• PLC Basic Network Elements
• PLC Gateway
• PLC based Topology
• Communication Techniques
• Medium Access Control Issues
• PLC Channel
• Important Issues
• International Standards
• References

3. INTRODUCTION
WHY POWER LINE COMMUNICATION BECAME IMPORTANT......?
• The usage of the power grid for control, maintenance and charging
purposes by the utility commodities.
• The liberalization of telecommunications.
• The deregulation of electricity utilities, which have added new
dimensions to the potential application of the electricity infrastructure.
• The birth and growth of the Internet has accelerated the demand for
digital telecommunications services to almost every premises.
A truly universal information superhighway might be realized,
with the capability of providing interconnection to every home,
factory, office, and organization.

4. • Power Line Communications (PLC), also known as Broadband Power Line
Access (BPL), is the latest technology to provide broadband Internet access
through existing house wiring.
• Every outlet in the home becomes a high-speed Internet access point.
Access from the in-home network.
• Long-haul networks can be established with other devices or facilities, such
as wireless (WiFi) and digital subscriber loop (DSL).
• This technology has the potential to offer benefits relative to regular cable,
DSL or wireless connections.

5. POWER LINE COMMUNICATION SYSTEMS
Power line communication is the usage of electrical power supply networks for
communication purposes.The main idea behind PLC is the reduction of cost and
expenditure in the realization of in-home PLC networks.
Power Supply Networks
• High Voltage (110-380kV) networks : Connnect the power stations with large supply
regions or big customers.
• Long Distances, power exchange with in a continent.
• Overhead supply cables.
• Medium Voltage(10-30kV) networks : Supplies larger areas,cities and big indutrial or
commercial customers.
• Overhead supply cables and underground networks.
• Low-Voltage(230V in Germany) networks: Supply the end users either as individual
cutomers or ass single users of a bigger customer.
• Overhead and underground cables.

6. A typical European power distribution network

7. Types of PLC Architecture
Narrowband PLC
• A Band for power supply Utilities, e.g. Energy related
services.
• B and C Band for private uses, e.g. For building and
home automation.
• Data Rate upto few thousands bits per second.
• Maximum distance covers upto 1 k.m.
• Needs repeater for long distance technique.
Modulation scheme that can be used
• ASK(Amplitude shift key) not rohbust againt
disturbances, therefore not good for PLC networks.
• FSK(Frequency Shift key), comperatively better then
ASK.
• BPSK(Binary Phase Shift key), it is complex but quite
commonly used.
• OFDM(Orthagonal Frequency Division Multiplexing,
much more rohbust against disturbances,which makes
it good for PLC networks.
CENELEC STANDARD bands for PLC

8. A general architecture for energy services

9. Structure of an autonomous system using narrowband PLC

10. Broadband PLC
• Broadband PLC Systems provide significantly higher data rates(more than 2 Mbps) than
narrowband PLC Systems.
• Broadband PLC networks offers the realization of more sophosticated telecommunication
services, e.g. Multiples voice connection, high speed data transmission, transfer of video
signals, also narrowband services as well.
• A wider frequency spectrum is needed (up to 30 MHz) due to EMC(Eletromegnatic
Compatibility), than it provides with in the CENELEC bands.
• On the otherhand, PLC network acts as an attenna becomming a noise source for other
communication systems, e.g, radio services.
• PLC has to operate with a limited-signal power, which decrease their performance(data
rates, distances).
• Low Voltage PLC technology is used for the realization of the so-called “last mile”.

11. Power-Line Broadband access Architecture
reference: http://cictr.ee.psu.edu/research

12. In Home PLC Network
• In –home PLC(indoor) systems use internal electrical infrastructure as
transmission medium.
• PLC LAN with in houses, which connect typical devices in a private home like
telephone computer, printer, vedio devices and so on.
• A base station controls an in-home PLC network and connects it to the outdoor
area.
• All devices are connected via a PLC modem.
• The modems are connected to the wall power supply sockets(outlets)
which are available in the whole flat.

13. In Home PLC Network

14. PLC BASIC NETWORK ELEMENTS
• The communication signal has to be converted
into a form that allows the transmission via
electrical networks.
• The main task of the basic elements is signal
preparation and conversion for its transmision
over powerlines as well as signal reception.
• Following two devices exits in every PLC access
network: PLC modem, PLC Base Station.
PLC Modem
• A PLC modem connects standard communication
equipment, used by the subcribers, to a
powerline transmission medium.
• Functionality of the physical layer i.e. Modulation
and Coding.
• Functionaliy of the Data Link Layer including
MAC and LLC.
PLC Modem:

15. PLC Base/Master station
• A PLC base station connects a PLC
access system to its backbone network.
• Provides multiple network
communication interfaces, such as
xDSL, Synchronous Digital
Hierarchy(SDH) for connection with a
high-speed network, WLL for wireless
interconnection and so on.
Coupling
• The coupling has to ensure a safe
galvanic seperation and act as a high
pass filter dividing the communication
signal above 9 kHz from the electrical
power(50 or 60Hz).
PLC Base Station

16. REPEATER
• To make it possible to realize the longer network distance in a low-voltage supply
network.
• Divides a PLC access network into several network segments.
• Network segments are seperated by using different frequency bands or by
different time slots.
Repeater

17. PLC network with Repeaters

18. PLC GATEWAYS
• A gateway is used to divide a PLC access network and an in-home PLC
network.
• It can be placed anywhere in a PLC access network to provide both signal
generation (repeater function) and network division on the logical level.

19. Gateways in the PLC Access Network

20. Topology of the Distribution Networks

21. Star Topology

22. Ring Topology

23. PLC Network Management

24. COMMUNICATION TECHNIQUES
• Modulation Technique:
Depending on the target application, each modulation technique has certain advantages.
• CDMA: For higher data rates up to 1Mb/s CDMA offers the advantage.
• FSK: For a lowest-cost and low-data-rate power line system FSK seems to be a good
solution. Transmission rates between 0.8 Mb/s to 2.4 Mb/s, depending upon which kind
of FSK and coding technique used.
• OFDM: Transmission rates up to 10 Mb/s can he achieved.
Coding Technique:
• A transmission scheme (in agreement with the existing CENELEC. norms) combining M-
ary FSK modulation with diversity and coding can make transmission over power lines
robust against permanent frequency disturbances and impulse noise.
Transmission rates up to 2.4 Mb/s can be achieved.

25. MEDIUM ACCESS CONTROL ISSUES
• Medium Access control (MAC) techniques are candidates for this communications
environment:
Protocols used:
• Fixed access, dynamic protocols with contention.
• Arbitration protocols (token, polling)
• Reservation protocols.
• Most traffic is expected to be from and to a terminal serving as the network gateway.
• Polling and Aloha are two of the most studied protocols for medium access.
• Aloha is the low throughput as the offered load increases, as well as its lack of support
for Quality of Service (QOS).
• Polling can handle heavy traffic and inherently provides quality of service guarantees.
• Carrier Sense Multiple Access (CSMA) is also proposed with overload detection. CSMA
is efficient under light to medium traffic loads.
The primary advantage of CSMA is its low implementation cost, since it is the dominant
technique in today’s wired data networks.

26. The data link layer of the OSI model used for power line protocol.

27. THE PLC CHANNEL
• Power lines constitute a rather challenging medium for data transmission.
Varying impedance, considerable noise, and high attenuation are the main
issues.
• Transmission environment for PLC is more complex as that of common
mobile communication.
A Simple Channel for PLC

28. IMPORTANT ISSUES
• Impedance, considerable noise, and high attenuation are the main issues.
• EMC( Electromagnetic Compatibility), due to which transmission of data is
limited to 2Mb/s to 4Mb/s.
• Transmission of data rate at Low Voltage to many subcribers also reduces
the performance of data rate through the PLC Network.

29. Influence of various disturbance sources

30. INTERNATIONAL STANDARDS
• IEEE 1901, Broadband Power Line Standards.
• ITU-T G.9960 Standards.
• CENELAC Standards.
• ETSI Standards.

31. References
• Book: Broadband powerline communications networks: network design, Halid Hrasnica,
Abdelfattah Haidine, Ralf Lehnert.
• Research Paper : Power Line Communications: State of the Art and Future Trends, Niovi Pavlidou,
Aristotle University of Thessaloniki, A. 1. Han Vinck, University of Essen, Javad Yazdani and Bahram
Honaty, University of Lancaster.
• Research Paper: A feasibility study of powerline communication technology for digital
inclusion in Brazilian Amazon,Jorge A. M. de Souza*a, Marcelino S. da Silvaa, Carlos R. L.
Francêsa,João C. W. A. Costaa, Ádamo Santanaa, Marcelo E. V. Segattob, Flavio R. Antonioc,
Gabryella Rodriguesa.
• Research Paper: Power Line carrier power line system, Master Thesis Khuram Hussain Zuberi,
Department of Microelectronics and Information Technology,Royal Institute of Technology, IT-
University,Kista,Stockholm,Sweden.
• Research Paper: Implementation of a Bandwidth-Efficient M-FSK Demodulator for Powerline
Communications,Gerasimos Maniatis, Kostas Efstathiou, Georgios Papadopoulos Department of
Electrical and Computer Engineering, University of Patras.

32. THANK YOU
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