Connection Type
Broadband Delivery Methods
There are a number of ways that broadband can be delivered to your home or business
1. Over a physical infrastructure such as copper telephone wires or over a cable system which could be either a copper or fibre-optical system.
2. Mobile broadband networks
3. Radio - Microwaves from radio installations nearby - called base stations
4. Satellite - Microwaves from satellites that orbit the earth in such a manner as their location in the sky remains the same (geo-stationary satellites).
There are advantages and drawbacks of each type of delivery method.
Copper Telephone Wires
The most common form of broadband delivery is via the same copper cables that currently provide telephone services. The technology to do this is known as DSL (Digital Subscriber Line). Its advantage is that it is inexpensive meaning that lower cost broadband services can be provided, but it is limited by the quality and length of the actual copper wire between your premises and the telephone exchange from which the copper cable originates. DSL comes in several forms.
ADSL (Asymmetrical Digital Subscriber Line) is delivered over the copper telephone wires and has a range of around 3.5km at 2Mbs, of about 6km at 1Mbs. Beyond 6Kbs speed reduces to 512Kbs. The main characteristic of ADSL is that it delivers higher speeds downstream and lower speeds upstream. This might seem odd but in most cases there is a far greater need to download information (that means delivering information to you) than the need to upload or send information. So ADSL services make better use of the large, but limited, capacity of the core telecommunications networks.
SDSL (Symmetrical Digital Subscriber Line) is also delivered over copper telephone wires and provides the same speed downstream and upstream over similar distances to ADSL. It is typically used in business where the need to send information is as great as the need to receive it.
Mobile Broadband
A new phenomenon emerging is mobile broadband technology provided by the mobile phone networks. The availability of getting a mobile broadband connection varies from each of the providers (Vodaphone, T-Mobile etc) depending on whether a ‘high speed’ 3G service is available. Many rural areas do not yet have access to 3G and as such connection speeds are often very slow. Each of the networks offering mobile broadband has coverage maps on their website showing where broadband services are available, so check these out before you buy. If you are planning to use mobile broadband extensively in a non-3G area then this may not be your ideal solution. Getting connected to a mobile broadband service is surprisingly easy. Your provider will supply a USB ‘dongle’ (similar to a memory stick) and a SIM card which you place in the dongle, you then slot the device into a USB port on your PC and away you go. There are no ISP settings to enter, no password or username settings and no fiddling around with security settings, it is virtually ‘plug & play’. Another great benefit is that you can use the dongle in as many computers as you wish, and it can be a useful backup if your home ADSL broadband connection breaks down. The download speeds achievable, like ADSL, are dependant on a number of variables such as contention ratios, signal strength and electronic interference, however speeds of up to 2 Mb/sec should be achievable which should be fast enough for e-mail access, web browsing and streaming video, from BBC i-Player for example, whilst out and about, but bear in mind that download speeds outside a 3G area are often very slow.
Cable
Generally this is only available where cable TV is installed, one 6MHz TV channel is allocated for data in each direction. This method can provide up to 27Mbs, which is shared across all the homes in the sub network. Generally services offered have been 512Kbs downstream and 128Kbs upstream although that is now changing with higher speeds being offered.
Radio
There are a number of radio bands available including:
28GHz Band which has bandwidth of 2Mbs and up, aimed at the Business to Business market, available over a range of about 4-5km.
5.8GHz Band provides shared access offering 512Kbs downstream and 128Kbs upstream with a range out to 4-5Km.
Satellite
The satellites have Geostationary Orbits at approx 36000Km from Earth. The service area is set by what is known as the ‘footprint'. Users within the service area require a dish aimed at satellite, the size of the dish varies with the speed required.
Two types of connection are offered, these are either one-way or two-way satellite. One-way provides downstream connection with the upstream being via a telephone line. Two-way provides connection downstream and upstream.
Current speeds vary from provider to provider but can give 2Mbs downstream and 256Kbs upstream.
Satellite delivery can suffer from latency problems, (slight delay caused by the signal travelling up to the satellite from the sender and back down again to the receiver) which means that the use of applications such as video-conferencing may not be of the quality preferred.