Technologies

Broadband Definition

The term ‘broadband’ refers to Internet connections with speeds significantly greater than those achieved with dial up modems. Broadband connections are generally ‘always on,’ that is, they are available instantaneously whenever someone wants to use them. This is in contrast to dial-up modems, where a user may have to wait for up to a minute or so before a connection is established.

There is no strict lower limit to speeds that are considered ‘broadband,’ although there is general agreement that speeds must be several hundred kilobits per second (200-300Kbps) to qualify. A functional description might specify that a broadband connection must support at least one good quality media stream, such as a YouTube video. Many people feel that a broadband connection must offer at least one megabit per second (1Mbps) for wireless, and 3-5Mbps for wired connections.

There is no upper limit to the definition of broadband speeds, although there is a practical limit of about (50-100Mbps) under technologies in wide deployment currently in the U.S. More typical speeds range from just under 1Mbps to about 15Mbps.

The NTIA and/or USDA may define lower limits for services that they will invest in under the ARRA. The following discussion makes no assumptions relative to that possibility.

Broadband Technologies:

There are multiple broadband technologies, each with its own advantages and disadvantages. One class of technologies delivers signals over fixed wires or fiber optic cables. A second delivers signals wirelessly via radio transmissions.

Fixed-line Technologies:

The predominant fixed line broadband Internet technologies in the U.S. today are cable and DSL. Some Telcos offer fiber optic connections, for example under the names FiOS and U-Verse. There are also a small number of broadband over power lines (BPL) deployments, in which Internet signals piggy-back over electric power distribution lines.

Technology                              Medium                                       Typical Rates (Mbps)
DSL                                          Telephone Lines                            0.75 -     8
Cable*                                      CATV Cables                                   5      -   15
FiOS/U-Verse                          Fiber Optic Cabling                     15      - 100
BPL                                           Electric Power Lines                    0.25  -    1

*DOCSIS 3.0                             CATV Cables                                 30      - 100

Wireless Technologies:

There are three main categories of wireless technology in use to provide broadband Internet access. These are cellular systems, satellite systems, and WiFi systems.

Technology                           Transmission Source                    Typical Rates (Mbps)
Cellular Data                         Cell towers                                      0.2 -   5
Satellite                                 Geo-stationary satellite                1     - 24
WiFi                                       Ad-hoc local arrangements            0.5 -    3

Within the category of cellular data systems, there are multiple modulations currently in use, and others announced or in early deployment. Current systems include, EDGE, GPRS, 1xRTT, HSDPA and EV-DO. Next generation systems include WiMax, in trials in some locations, and LTE.

Discussion of Technologies:

Generally speaking, fixed line technologies deliver higher bandwidth for equivalent cost relative to wireless technologies.

Wireless technologies offer tremendous flexibility. They may offer attractive solutions in sparsely populated areas, where the cost can be prohibitive to install miles of wire for each user connected. In those areas and in other areas where for other reasons the cost of installing wired infrastructure is exorbitant, delivery of broadband Internet services via wireless connections may be the most efficient approach.

An exception may be BPL, Broadband over Power Lines. This technology delivers data over existing power lines, and may be competitive with wireless delivery of Internet services in sparsely populated areas for which DSL or cable deployment is uneconomic.

Wireless services designed around WiFi (Wireless Fidelity) systems may offer workable solutions in many areas. Another possibility is 3G cellular data services. Such services can be surprisingly cost-effective for users who consolidate all their communication services to a smart-phone. The cost of Internet plus phone services for such a device can be less than the cost for separate land line telephone plus Internet services.

In especially remote or rugged regions, the only plausible approach may be to deliver Internet services via satellite. Satellites have the advantage that their signals may reach the entire geographic extent of the country. Their disadvantage is that they generally offer bandwidth at the lower limits of broadband speeds. Also, they are generally not bi-directional connections. That is, satellites may deliver Internet content to users, but users may not be able to send signals directly back to the satellite. A satellite Internet user must have a second means available such as a dial-up modem in order to send signals to the Internet.

Another issue—what does the user use to access the Internet?

The agencies may want to consider what equipment end users will use to access the Internet. Typically this would be a PC. Given that for some targeted users a PC may be out of reach either because of expense or complexity, it may be worth paying some attention to the question.

Possibilities: 
     Netbook PCs 
    ‘Kiosk’ PCs that are designed to offer only a browser (“cloud” computing via Google Docs, Office Live Workspace, and Zoho) 
    Set-top box that connects TV to Internet