Page last updated at 09:10 GMT, Wednesday, 27 May 2009 10:10 UK

The face of future broadband

The UK is beginning to roll out next-generation broadband with BT committed to a £1.5bn spend on fibre optics and Virgin Media extending its cable network.

Lord Carter is due to offer the government's vision of how super-fast broadband can be delivered to as many UK homes as possible.

Find out more about the technologies that could one day deliver faster broaderband to your home.

ADSL2+VDSLSatelliteMobileWimaxCableFibre Optic Cable

FIBRE TO THE HOME

Fibre to the home would bring speeds of between 50Mbps and 100Mbps, with the added benefit of being able to offer those speeds both upstream and downstream. This would make contributing back to the net - sending video files for instance - much easier.

Unlike DSL technologies - which are carried along copper cables - it is not subject to noise issues.

Fibre optics are encased in cable similar to an ordinary PC cable but inside are tiny, hair-size fibres of many colours. They are used to transmit digital information in the form of light signals

Providers such as BT would lay ethernet over the fibre in order to provide services.

The biggest problem issue about fibre is the cost. To provide fibre to the home across the UK would cost up to £15bn.

BT is the most likely candidate to provide such a network and while it has committed itself to putting fibre in all new-builds, nothing else has yet been decided.

FIBRE TO THE CABINET

This is the cheaper option than fibre optics - UK estimates are about £5bn for a nationwide rollout - and it is basically a hybrid solution utilising both copper and fibre.

To provide FTTC across the UK will require the building of 90,000 new street cabinets - where wires from the telephone exchange are kept at street level.

It is capable of supporting new high bandwidth applications such as HDTV, as well as telephone services such as voice-over IP and general internet access, over a single connection.

It will not deliver the same speeds as fibre to the home, with a maximum of around 60Mbps.

As with ADSL, speeds will be dependent on how close people live to the street cabinet.

The final part of the connection to the home would run over ADSL or the latest flavour of ADSL, known as VDSL2.

VDSL2 can provide data rates exceeding 100Mbps in both the upstream and downstream directions.

ADSL2+

This variant of existing DSL is being rolled out in the UK from April 2008 with every exchange enabled by 2011.

The arrival of ADSL2+ is closely linked to work BT has been doing on its core network, upgrading it to an IP infrastructure in a project known as the 21 century network. ADSL2+ offers speeds of up to 24Mbps, but as it is distance-dependent a lot of people will not actually achieve those kind of speeds.

Because the copper lines it operates on pick up electro-magnetic noise the line can be affected by some unusual issues, such as noisy fridges.

Old houses with old internal wiring will also affect the service, with possible breaks in service or speed slowdowns.

WIMAX

Wimax stands for Worldwide Interoperablity for Microwave Access. It is based on the IEE 802.16 standard, also known as WirelessMAN.

It is often referred to as wi-fi on steroids, because of its ability to provide wireless data over much longer distances than wi-fi.

In countries with good fixed line infrastructure, WIMAX acts as a filler but in some developing countries is can be the dominant infrastructure for broadband access. Countries such as Pakistan are planning nationwide WIMAX rollouts.

It is possible for WiMAX to deliver speeds of up to 70Mbps and operate over distances of up to 50km, although not concurrently.

CABLE

Cable Broadband has three major parts - the customer cable modem (which connects to the customers PC or laptop), the cable TV network (through which the signal flows) and the main cable router (which take the customer signal off the cable TV network and passes it on to the Internet).

The system which is used, or "the protocol", is called DOCSIS (Data Over Cable Service Interface Specification).

Currently DOCSIS 1.0 offers speeds up to 38Mbps. The new system, called DOCSIS 3.0, could offer up to 120Mbps and higher. This (D3) is currently in trial at 50Mbps in selected regions of the UK, such as Ashford, Folkestone and Dover.

The system is always on, it is not dependent on the distance you are from the exchange (unlike ADSL) and every person can receive the same speeds - unlike ADSL.

The electronics are a mixture of fibre and copper cable, with the majority being fibre. Only the last part to the customer is copper which means that cable broadband has the potential to offer far greater speeds now, and in the future, compared to its DSL rival.

SATELLITE

It is estimated that there are some 25 million rural homes around Europe with no broadband access. For some the answer could be satellite.

Two broadband satellites are being launched in the next year - the first from UK firm Avanti, due to go up at the end of the year, which is promising to offer 2Mb for all UK homes for around £15 a month.

The second is from French firm Eutelsat, which it says will offer the entire UK up to 10Mbps.

Its Tooway satellite will use the Ka band of the microwave spectrum to offer faster speeds.

The price tag will be welcome news to consumers as previously satellite broadband came with around a £50 a month fee. Set up costs - users will need a dish and a modem to send and receive data - will still be around £400.

The delay as information is sent to the satellite and then out to the internet and back to the user - about 1.5 seconds for downloading a standard website - could cause frustration for some users.

Upload speeds of around 384 kilobits could also be a problem.

MOBILE BROADBAND

Touted by many as the way to fill in the UK broadband gaps, mobile broadband comes either as a dongle or via a wireless router.

Mobile broadband can be delivered from a range of technologies from 2G to 3G, with the highest speed currently possible in the UK being 7.2Mbps (megabits per second)

With the advent of 4G technologies, and many are backing so-called LTE (Long-Term Evolution), which is due to come to the UK within the next two years, speeds are set to get faster.

Most people will have some form of mobile coverage in the UK but it could be intermittent. For example, a lorry passing in front of a house could cut the signal off.

The other big issue for mobile broadband is the amount of data available. While fixed broadband offers data allowances of up to 10Gb (gigabytes) a month or beyond, mobile data allowances are much smaller.

A £10 a month fee may buy a user around 3Gb of data - if they exceed this they have to pay a premium which ranges from a few pounds per extra gigabyte to several hundred pounds.

There are also concerns about whether mobile broadband can remain stable when many people are using the service.



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