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Creating Digital Britain

From CAD User AEC Magazine Vol 22 No 7 - JULY/AUGUST 2009

A lot has been said in the press recently about Britain falling behind in the Broadband stakes. Powerline Communications holds the key to delivering Digital Britain - at far less cost to the British taxpayer than setting up nationwide fibre optic networks. Ann Whyte, Director Corporate Communication at DS2, shows how it can be done. Architects and civil engineers also need to factor in the latest communication technology that will shape the way we work and live in the future

Internet providers are set to pump billions of pounds into fibre-optic connectivity over the next ten years, in a bid to not only increase broadband speeds, but also stamp out 'not-spots' areas where broadband is unavailable. There is a simple, reliable and cost- effective alternative to create the Digital Britain though; through powerlines that already exist.

Powerline Communications enables a broadband connection to be sent anywhere in a home by using the existing electrical wiring available in every room. This type of communication can work regardless of the back-haul technology used to provide a broadband connection. As long as a broadband connection is available, powerline technology can be used to extend this connection to any socket inside a house.

For example, IPTV (Internet Protocol Television) services - where the technology used for the back-haul technology is xDSL-based - uses powerline communications to create a secure home network. In this case, service providers need a cost-effective and easy- to-use solution to connect a set-top box, located next to a television set, to the broadband modem, which is usually located in a different room somewhere in the house.

Typically, the broadband connection is

fed through a powerline adapter, which can be plugged into any socket in the house. By doing this, all the remaining sockets in the house automatically become an interface to the home network. Every electrical point in the home can now pick up a video stream, digital audio, digital data or a live Internet connection, instantly and without interruptions. By simply connecting a pair of adapters to any existing socket in the house, a home network is created in a matter of seconds.

HOW DOES IT WORK?

Powerline Communications technology uses electrical wiring for high-speed transmission of data. It is a more competitive solution to the connectivity problem than that of other wired solutions or wireless technologies. It has the capability of offering the data rate, performance, flexibility, reliability and cost- efficiency required to support whole-home multimedia networking.

The electrical wiring used by Powerline Communications for data transmission is considered to be a harsh and unfriendly environment and one of the most difficult communications channels. It is a channel known for real-time variations, impulsive and periodic noise sources, sudden impedance changes and several bifurcations creating reflections and other undesirable effects.

Most powerline communications technology implements advanced OFDM (Orthogonal Frequency Division Multiplexing) modulation, a scheme that overcomes most channel difficulties to achieve high data rates while keeping power transmissions levels low.

OFDM was selected as the most suitable modulation scheme for the powerline channel in particular because it is:

• The most immune to interference, being able to cope with severe changes in channel conditions • Provides the highest level of spectral efficiency and performance Several leading powerline communications technology providers use OFDM modulation based on the simultaneous transmission of more than one thousand carriers over a frequency band of 30MHz, usually starting at 2MHz and ending at 32MHz. The data to be transmitted is divided between all sub- carriers with a number of bits assigned to each sub-carrier.

One of the great advantages of some OFDM implementations is that the signal strength and the frequency spectrum used is fully adaptable and configurable. This means that commercial products can be tuned taking into account any type of regulation either by adding notches to allow for coexistence with Radio Amateur signals, reducing the signal strength or limiting the frequency spectrum used.

At the same time, Powerline Communications uses some of the most advanced Forward Error Correction (FEC) algorithms, enabling semiconductor vendors to add redundant bits to every data frame and thus allow for information recovery in the event of errors in received frames.

All these very complex algorithms and their corresponding silicon implementations are required to transmit in one of the most complex mediums, if high data rates in the order of 200+Mbps data rate are desired.

UTILISING EXISTING INFRASTRUCTURE

Powerline Communications (PLC) technology not only enables the creation of a fast, reliable and secure network that can reach areas that other technologies aren't able to service, but also does so without the need for installili expensive new wires or having to limit the amount of applications. The technology has been developed to survive the very hostile environment of electricity lines and to adapt to all existing coaxial cabling, electrical wiring or phone lines already in the home - making it usable over any wire

-which offers the speed, coverage and Quality of Service (QoS) that is required for the government's Digital Britain Powerline Communications technology addresses two fundamental issues that reside at the core of the government's attempt to reshape the future of the UK broadband environment:

1. Coverage -whole home coverage is a key element for digital home applications and wired networking, such as over powerline, coax or phone line cable, has a number of demonstrable advantages over wireless. It provides better coverage where coverage is defined as the likelihood of achieving a certain speed in the deployment location. It enables high- speed data exchange and High Definition video without service latency, for pixel-free streaming.

PLC technology, when used in existing power lines, offers an extensive infrastructure that allows connectivity across a house because there are a number of power outlets available in each room, offering greater connectivity.

2. Quality of Service -unlike wireless and other wired technologies, 'anywire technology' uses TDMA (Time Division Multiple Access) to guarantee the availability of time-sensitive communications such as VoIP and Video streaming. One data stream can easily be prioritised over another and assures that latency and bandwidth are sufficient for the high priority traffic. For example, in a home network a Skype Videoconference traffic stream receives higher priority than web browsing and Torrent clients, to guarantee the quality of the call. PLC technology is secure, implementing 3DES encryption without the complex configuration options of WiFi, and it is scalable, with guaranteed QoS at the MAC layer without collisions, delivering sufficient throughput for video even in a dense multi-dwelling environment.

In addition, initial dual play offerings, where voice and data are typically distributed around the home using wireless, can be transformed into a successful triple play offering, where IPTV video content is distributed around the home by plugging in the high-speed powerline adapters. There is no need to drill and no need to lay new cable.

THE SIMPLICITY OF UNIVERSAL 'PLUG AND PLAY'

PLC technology is literally 'plug and play' an immediate out-of-the-box experience essential for self-install networked entertainment services. There is definitely

a growing consumer demand for easy-toinstall, high-speed in-home networking, and this method of creating a Digital Home is preferable to many other options because it is a simple 'plug and play' option. As the industry continues to grow, consumer choice will develop - along with pressure for solutions that are future-proof and user-friendly.

NEXT-GGENERATION HOME NETWORKS

DS2's next-generation powerline products operate at a peak data rate of 400Mbps and will be available in all next-generation products powered by DS2 technology to satisfy the demands for extra bandwidth in the digital home. For example, 400Mbps technology will enable the development of new HD-capable multimedia applications, such as multi-channel HD-IPTV delivery or multi-room PVR (Personal Video Recorder) that will require bandwidth sufficient to support five or more simultaneous video streams.

Traditional telephone companies have started to offer IPTV (Internet Protocol Television), an offering usually reserved to cable companies and other television providers. In order to cost-effectively meet subscriber acquisition targets, home networking technology should be easy to use, capable of being installed by any subscriber without assistance (plug-andplay), and operate without interfering with existing broadband access infrastructure technologies, like VDSL.

As next-generation home networks continue to take shape, a standard for networking over any wire is already in motion - the G.hn standard. The goal of a single standard for home networking over all wires means that all products - present and yet to be developed - will be interoperable with each other. Powerline companies are continuing to work towards compliant silicon chipsets, as well as future 1Gb technology. www.ds2.es or www.http//.blog.ds2.es

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