Power Line Communications (PLC)

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Power Line Communications(PLC)

• Muhammad Salman Yousuf,
• Department of Electrical Engineering, KFUPM.

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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

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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

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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

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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

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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

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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

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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

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Modern Applications and Prospects (Contd)

• 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

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Modern Applications and Prospects (Contd)Last
mile and Last inch access
Last-mile access
Last-inch access
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Modern Applications and Prospects (Contd)

• 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

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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

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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

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Issues / Problems (Contd)

• 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

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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

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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

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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

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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
• Doesnt 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

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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

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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

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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

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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

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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

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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

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HomePlug 1.0 Standard
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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

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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 QA session if you are interested

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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

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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

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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

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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

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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

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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

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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

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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

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