Power Line Communications (PLC)

1. Power Line Communications(PLC) Muhammad Salman Yousuf, Department of Electrical Engineering, KFUPM.

2. Outline • Introduction • A bit of history • Modern applications and prospects • Issues / Problems • Layers, Access Methods and Protocols • Various Standards • HomePlug Powerline Alliance Standards • IEEE Standards • More topics • PLC usage in Saudi Arabia

3. Outline • Introduction • A bit of history • Modern applications and prospects • Issues / Problems • Layers, Access Methods and Protocols • Various Standards • HomePlug Powerline Alliance Standards • IEEE Standards • More topics • PLC usage in Saudi Arabia

4. Introduction • Power Lines, originally devised to transmit electricity from a some sources to many sinks • Operation frequency: 50-60 Hz • Power cables, lines and towers are some of the most robust structures • Power Lines can be used for communication as well • Data is modulated on a carrier frequency and sent over • Can use existing infrastructure for data traffic • Can also provide many other benefits • Involves a lot of technicalities and expertise

5. Outline • Introduction • A bit of history • Modern applications and prospects • Issues / Problems • Layers, Access Methods and Protocols • Various Standards • HomePlug Powerline Alliance Standards • IEEE Standards • More topics • PLC usage in Saudi Arabia

6. PLC has a bit of history… • PLC has been around for quite some time • Initially, data over PLs was used for protection • Telemetry purposes (1922) (15 – 500 kHz carrier frequency) • Consumer products like baby alarms (1940) • Automated meter reading (1970s) • All these were low bit rate applications • But now due to advancements in VLSI and DSP, PLC has received renewed attention…

7. Outline • Introduction • A bit of history • Modern applications and prospects • Issues / Problems • Layers, Access Methods and Protocols • Various Standards • HomePlug Powerline Alliance Standards • IEEE Standards • More topics • PLC usage in Saudi Arabia

8. Modern Applications & Prospects • Radio Broadcasting • Used widely in Germany, Switzerland, Norway, Russia… • Radio program fed by special transformers into lines • Filters installed in substations and line branches • Automotive • Digital Transmission of data over DC power lines inside the car • Advanced digital communications techniques used • One power line can be used for multiple separate networks • Protocols used: CAN-bus, LIN-bus, DC-bus • Applications: Climate control, Multimedia, Instrumentation, Mechatronics

9. Modern Applications and Prospects (Cont’d) • Home Automation (X10 Standard, 1975) • Home Networking and Internet (BPL) • Last mile access – to the home • Last inch access – to the devices inside the home • In-home networking could transform all power outlets in our homes into broadband connections for PCs, phones and many other ‘enable’ electrical appliances • BPL can also be used as backhaul for wireless communications and WiMAX networks • BPL as backup • No universal standard, although HomePlug is popular

10. Modern Applications and Prospects (Cont’d)Last mile and Last inch access… Last-mile access Last-inch access

11. Modern Applications and Prospects (Cont’d) • PLC has been used for specific problems as well • Practical Intelligent homes • Remote detection of illegal electricity usage • Quality monitoring of power systems and power

12. Outline • Introduction • A bit of history • Modern applications and prospects • Issues / Problems • Layers, Access Methods and Protocols • Various Standards • HomePlug Powerline Alliance Standards • IEEE Standards • More topics • PLC usage in Saudi Arabia

13. Issues / Problems • Design • Varying Impedance • Noise • Impedance • Varying Channel Model • High dependence of location of transceivers • Reflection • No Line of sight • Echoes • Multipath Fading • Attenuation

14. Issues / Problems (Cont’d) • Noise • Not Gaussian • Sources: Brush motors, bulbs and lamps, switching power supplies, dimmers, power tools etc. • Power lines can catch radio and ISM band signals • Mainly four types of noise are present • Generalized Model

15. Outline • Introduction • A bit of history • Modern applications and prospects • Issues / Problems • Layers, Access Methods and Protocols • Various Standards • HomePlug Powerline Alliance Standards • IEEE Standards • More topics • PLC usage in Saudi Arabia

16. Layers, Access Methods and Protocols • Communications in PLs can be divided into • The Physical Layer • Defines modulation techniques • FSK, CDMA, OFDM • The Medium Access Control Layer • Specifies resource sharing strategy • Specifies protocols

17. The Physical Layer • Defines Modulation Techniques • FSK – Frequency Shift Keying • Low cost, low data-rate applications • Like protection and telemetry • CDMA – Code Division Multiple Access • Data rates up to 1Mbps • OFDM – Orthogonal Frequency Division Multiplexing • Data rates above 1Mbps • Broadband

18. The Medium Access Control (MAC) Layer • Specifies access and resource sharing protocols • MAC has two categories of access schemes • Fixed Access • Assigns each user fixed channels • Doesn’t care if the user needs it or not • Not suitable for traffic in bursts, like internet, data etc. • Dynamic Access • All users can use the channel when they need it if it is free • Contention based protocols – collisions occur • Arbitration based protocols – collisions avoided / collision free • Examples of MAC protocols are: Polling, Aloha, Token schemes, CSMA/CA/CD • HomePlug standard uses CSMA/CA

19. Outline • Introduction • A bit of history • Modern applications and prospects • Issues / Problems • Layers, Access Methods and Protocols • Various Standards • HomePlug Powerline Alliance Standards • IEEE Standards • More topics • PLC usage in Saudi Arabia

20. Various Standards • Many standards available, but none is very strong • X10 was the default standards up till now but has limited applications • OPERA – Open PLC European Research Alliance • POWERNET – European Commission • UPA – Universal Powerline Association * • CEPCA – Consumer Electronics Powerline Communications Alliance (Sony, Mitsubishi & Panasonic) • ETSI PLT • HomePlug Powerline Alliance * • IEEE *Strong standards

21. Outline • Introduction • A bit of history • Modern applications and prospects • Issues / Problems • Layers, Access Methods and Protocols • Various Standards • HomePlug Powerline Alliance Standards • IEEE Standards • More topics • PLC usage in Saudi Arabia

22. HomePlug Powerline Alliance • Trade group consisting of over 65 companies • Founded in March 2000 • Mission: To enable and promote rapid availability, adoption and implementation of cost-effective, interoperable and standards-based home power line networks and products. • Big players: Earthlink, General Electric, Intel, Linksys, Motorola, Radio Shack, Samsung, Sony, Sharp etc. • Contributions from multiple companies = Best of class performance • Defined the following standards • HomePlug 1.0 – connects devices in homes • HomePlug AV – transmits HDTV and VoIP in home • HomePlug BPL – still a working group for last-mile broadband • HomePlug CC – Command and Control to complement others

23. HomePlug 1.0 Standard • Developed in 2000 • Main features in the Physical Layer • OFDM • OFDM is well known in literature • Used in DSL, IEEE 802.11a/g, TV transmission • Specially tailored for HomePlug • Has 84 equally spaced subcarriers between 1-4.5 MHz • DBPSK and DQPSK completely eliminate equalization need • FEC and Data Interleaving • Uses turbo codes • Adaptive approach • Uses innovative modulation mechanism

24. HomePlug 1.0 Standard • Main Features of the MAC Layer • Modeled to work with the IEEE 802.3 frame formats • Appends Ethernet frames with encryption and management data • May use segmentation and reassembly • Two basic frame formats • Uses CSMA/CA • Allows up to four different priority levels • Uses a backoff algorithm to provide high network utilization even under heavy loads

25. HomePlug 1.0 Standard

26. HomePlug AV Standard • Next generation technology • Aims to provide high quality, multi-stream, entertainment oriented networking over existing AC wiring • Interoperable with HomePlug 1.0 Standard • Supports up to 200 Mbps channel rate and 150 Mbps information rate • Robust and successful in high noise environments

27. HomePlug AV Standard • Main Features of Physical Layer • 2 – 28 MHz frequency range • 200 Mbps channel and 150 Mbps information rates • Windowed OFDM • Uses power Turbo Convolutional Codes (TCC) • Modulation varies from BPSK (1 bit / carrier / symbol) to 1024 QAM (10 bits / carrier / symbol) – highly adaptive to varying channel characteristics between Tx and Rx • Separate inputs for data, control and HP 1.0 signals • More details in Q&A session if you are interested…

28. HomePlug AV Standard • Main Features of MAC Protocols • Connection oriented • Contention free • Supports both TDMA and CSMA/CA for efficiency • Four different priority levels • Has a central manager called CCo

29. Outline • Introduction • A bit of history • Modern applications and prospects • Issues / Problems • Layers, Access Methods and Protocols • Various Standards • HomePlug Powerline Alliance Standards • IEEE Standards • More topics • PLC usage in Saudi Arabia

30. IEEE Standards (or lack of them…) • IEEE P1675 "Standard for Broadband over Power Line Hardware" • working group working on hardware installation and safety issues. • IEEE P1775 "Powerline Communication Equipment - Electromagnetic Compatibility (EMC) Requirements - Testing and Measurement Methods“ • working group focused on • PLC equipment • electromagnetic compatibility requirements • testing and measurement methods • IEEE P1901 "IEEE P1901 Draft Standard for Broadband over Power Line Networks: Medium Access Control and Physical Layer Specifications" • working group for delivering broadband over power lines. • Delivery expected by 2008

31. Outline • Introduction • A bit of history • Modern applications and prospects • Issues / Problems • Layers, Access Methods and Protocols • Various Standards • HomePlug Powerline Alliance Standards • IEEE Standards • More topics • PLC usage in Saudi Arabia

32. More Topics • QoS (Quality of Service) Features • Guaranteed bandwidth • Fixed Latency • Quasi-Error free service • Jitter • Performance • Security Issues • HomePlug Deployment • Field Tests • HomePlug Service Providers • Regulations (like FCC in North America) and Compliance • Politics – Opposing groups, supporting groups & FCC

33. Outline • Introduction • A bit of history • Modern applications and prospects • Issues / Problems • Layers, Access Methods and Protocols • Various Standards • HomePlug Powerline Alliance Standards • IEEE Standards • More topics • PLC usage in Saudi Arabia

34. PLC in Saudi Arabia • ElectroNet with SEC since 2005 on a Pilot Project • Uses BPL over Medium Voltage Cables and linking into a Low Voltage distribution within a shopping mall. • Also integrates Automatic Meter Readers • SACMAC (Saudi Arabian Computer Management Consultants) • Signed a deal to become an official system Integrator and Distributor for Mitsubishi PLC. • Aims to end the monopoly of STC in providing broadband internet

35. Conclusions • Rapidly growing technology • Has tremendous potential to provide quality services at low cost • Has fueled research and advancement of technology and communications in general

36. Questions and Answers Dear friends, Point to note: I am the first and you all are left!!!