Power Line Communication

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

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

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.

• 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.

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.

A typical European power distribution network

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

A general architecture for energy services

Structure of an autonomous system using narrowband PLC

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”.

Power-Line Broadband access Architecturereference: http://cictr.ee.psu.edu/research

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.

In Home PLC Network

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:

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

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

PLC network with Repeaters

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.

Gateways in the PLC Access Network

Topology of the Distribution Networks

Star Topology

Ring Topology

PLC Network Management

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.

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.

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

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

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.

Influence of various disturbance sources

INTERNATIONAL STANDARDS

• IEEE 1901, Broadband Power Line Standards.

• ITU-T G.9960 Standards.

• CENELAC Standards.

• ETSI Standards.

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.

THANK YOU