Broadband is a digital or analog signal capable of carrying a large quantity of information because multiple signals share the bandwidth of the medium. It allows the transmission of voice, data, and video signals over a single medium. Broadband is not an end in itself, merely an enabling technology—a transport mechanism that provides access to what a user really wants.

Broadband services can be delivered using one of five possible technologies—fiber, fixed wireless access, satellite, cable, and DSL technologies. Cable and DSL are the most ubiquitous technologies in terms of broadband delivery, carrying nearly all of the world’s broadband traffic.

TECHNOLOGY OPTIONS
Wireless
l EDGE: Enhanced data rates for GSM evolution or EDGE is a 3G technology that delivers broadband data at high speeds to mobile devices. It allows consumers to connect to the Internet, and send and receive data including digital images, Web pages, and photographs about three times faster than GPRS. Using EDGE, one can deliver advanced mobile services such as downloading of video and music clips, full multimedia messaging, high-speed color Internet access and e-mail on the move.

Using EDGE, operators can handle three times more subscribers than GPRS, triple their data rate per subscriber, or add extra capacity to their voice communications. EDGE uses the same time-division multiple-access (TDMA) frame structure, logic channel and 200 kHz carrier bandwidth as today’s GSM networks, which allows existing cell network plans to remain intact.

l CDMA2000 1xEV-DO: A data-optimized version of CDMA2000 called 1xEV-DO provides peak rates of over 2 Mbps. With an average throughput of over 700 kbps comparable to wireline DSL services and fast enough to support demanding applications such as streaming video and large file downloads, 1xEV-DO devices will provide ‘always-on’ packet data connections, helping to make wireless access simpler, faster and more useful than ever.

l Terrestrial Wireless: Transmission of terrestrial microwave signals involves the installation of antennas at high points where line of sight is the clearest. Terrestrial microwave is used as an alternative to coaxial cable and fiber optic cable for long distance telephony. It is used for point-to-point and point-to-multipoint applications and can provide broadband access for subscriber-based applications. Another application is a high-altitude platform-station balloon (HAPS) operating at 32 GHz and 47/48 GHz.

Laser beams offer a further alternative, and are typically targeted on separate offices from a central location. The signal travels through glass and so is suited to the provision of spot services in office towers surrounding the source of the beam. Called Free Space Laser, one can expect speeds of up to 155 Mbps over a distance of up to 6 km.

Satellite
l VSATs: Using VSATs, enterprises can opt for greater bandwidth enabling a variety of multimedia applications. One can use it for Internet surfing, e-education and others.

Most of the VSAT service providers in India provide different kinds of services.

Wireline
On the wireline front, corporates do have a lot of options right from telephone cables to cable TV among others. On the copper wire—the traditional telephony local loop comprises twisted pair copper wires for telephony and data applications. One can go for DSL, ADSL, SDSL, SHDSL, and VDSL, and VoDSL. The various flavors of DSL have the potential to offer broadband access to wide sections of urban population.

l Digital Subscriber Line (DSL): This technology solves the bottleneck problem associated with delivering network services over phone lines. When a user receives digital information from the Internet over the phone line it is filtered and converted to analog for telephone lines, requiring the modem to change the data back into digital form. A DSL transmission is digital. It does not need this conversion. This allows the phone lines to carry more bandwidth for transmitting data. DSL achieves broadband speeds (greater than 1.5 Mbps) over ordinary phone lines. A DSL line can carry both data and voice signals and the data signal is continuously connected. There are different varieties of DSL, including asymmetric DSL (ADSL), symmetric high bit rate DSL (SHDSL), very high bit rate DSL (VDSL), G.Lite (also known as DSL-lite), and splitterless ADSL or universal ADSL.

l Asymmetric Digital Subscriber Line (ADSL): It is the most widely deployed form of DSL technology. ADSL uses most of the bandwidth available to transmit information downstream to the user and only a small part to receive information from the user. Typically, ADSL generates downstream speeds up to 8 Mbps and generates upstream speeds of up to 640 Kbps. Unlike cable technology, ADSL provides dedicated bandwidth, so its speed and capacity are unaffected by the number of homes or businesses using the service at the same time.

l Symmetric Digital Subscriber Line (SDSL): Also known as single line DSL, this is a technology that delivers a maximum data rate that is the same both upstream and downstream. Typically, SDSL generates speeds of 2.3 Mbps in both directions. However, SDSL does not use the available bandwidth in the copper lines very efficiently and, more importantly, it causes spectrum compatibility problems with other DSL lines running in the same cable bundle. For this reason, SHDSL is becoming the most widely used symmetrical DSL technology.

l Single-Pair High-speed Digital Subscriber Line (SHDSL): Also known as g.SHDSL, it can transport data symmetrically at rates ranging from 192 Kbps to 2.3 Mbps over distances up to 3,650 m.

l Very High-speed Digital Subscriber Line (VDSL): This transmits data over existing telephone lines at lightning fast speeds over relatively short distances. The shorter the distance, the faster the connection rate. In trials, VDSL has produced speeds between 51 and 55 Mbps over lines of up to 300 m. VDSL was developed to support exceptionally high bandwidth applications like high definition television (HDTV) and steaming video.

l Voice over Digital Subscriber Line (VoDSL): This technology delivers voice services over DSL using ADSL or SHDSL to integrate voice with data services. VoDSL solutions prioritize, multiplex, and transport multiple voice and data channels over a DSL connection to a gateway interface that provides connectivity between a data network and the public switched telephone network (PSTN).

l Coaxial Cable: Traditional cable TV networks have to be upgraded to facilitate two-way communications, for example, for Internet access or cable telephony. Often, this has been undertaken by laying a second copper wire alongside the coaxial cable.