Broadband Wireless


Broadband access by ADSL or cable provides teleworkers with faster connections than dialup, but until recently, SOHO PCs had to connect to a modem or a router over a Cat 5 (Ethernet) cable. Wireless networking, or Wi-Fi (wireless fidelity), has improved that situation, not only in the SOHO, but on enterprise campuses as well.
Using 802.11 networking standards, data travels from place to place on radio waves. What makes 802.11 networking relatively easy to deploy is that it uses the unlicensed radio spectrum to send and receive data. Most radio and TV transmissions are government regulated and require a license to use.
Beginning in 2007, computer manufacturers started building wireless network adapters into most laptop computers. As the price of chipsets for Wi-Fi continues to drop, it is becoming a very economical networking option for desktop computers as well.

The benefits of Wi-Fi extend beyond not having to use or install wired network connections. Wireless networking provides mobility. Wireless connections provide increased flexibility and productivity to the teleworker.
Until recently, a significant limitation of wireless access has been the need to be within the local transmission range (typically less than 100 feet) of a wireless router or wireless access point that has a wired connection to the Internet. Once a worker left the office or home, wireless access was not readily available.
However, with advances in technology, the reach of wireless connections has been extended. The concept of hotspots has increased access to wireless connections across the world. A hotspot is the area covered by one or more interconnected access points. Public gathering places, like coffee shops, parks, and libraries, have created Wi-Fi hotspots, hoping to increase business. By overlapping access points, hotspots can cover many square miles.

New developments in broadband wireless technology are increasing wireless availability. These include:
Municipal Wi-Fi
WiMAX
Satellite Internet
Municipal governments have also joined the Wi-Fi revolution. Often working with service providers, cities are deploying municipal wireless networks. Some of these networks provide high-speed Internet access at no cost or for substantially less than the price of other broadband services. Other cities reserve their Wi-Fi networks for official use, providing police, fire fighters, and city workers remote access to the Internet and municipal networks.
Most municipal wireless networks use a mesh topology rather than a hub-and-spoke model. A mesh is a series of access points (radio transmitters) as shown in the figure. Each access point is in range and can communicate with at least two other access points. The mesh blankets its area with radio signals. Signals travel from access point to access point through this cloud.

A meshed network has several advantages over single router hotspots. Installation is easier and can be less expensive because there are fewer wires. Deployment over a large urban area is faster. From an operational point of view, it is more reliable. If a node fails, others in the mesh compensate for it.
WiMAX (Worldwide Interoperability for Microwave Access) is telecommunications technology aimed at providing wireless data over long distances in a variety of ways, from point-to-point links to full mobile cellular type access. WiMAX operates at higher speeds, over greater distances, and for a greater number of users than Wi-Fi. Because of its higher speed (bandwidth) and falling component prices, it is predicted that WiMAX will soon supplant municipal mesh networks for wireless deployments.

A WiMAX network consists of two main components:
A tower that is similar in concept to a cellular telephone tower. A single WiMAX tower can provide coverage to an area as large as 3,000 square miles, or almost 7,500 square kilometers.
A WiMAX receiver that is similar in size and shape to a PCMCIA card, or built into a laptop or other wireless device.
A WiMAX tower station connects directly to the Internet using a high-bandwidth connection (for example, a T3 line). A tower can also connect to other WiMAX towers using line-of-sight microwave links. WiMAX is thus able to provide coverage to rural areas out of reach of "last mile" cable and DSL technologies.
Satellite Internet services are used in locations where land-based Internet access is not available, or for temporary installations that are continually on the move. Internet access using satellites is available worldwide, including for vessels at sea, airplanes in flight, and vehicles moving on land.
There are three ways to connect to the Internet using satellites: one-way multicast, one-way terrestrial return, and two-way.

One-way multicast satellite Internet systems are used for IP multicast-based data, audio, and video distribution. Even though most IP protocols require two-way communication, for Internet content, including web pages, one-way satellite-based Internet services can be "pushed" pages to local storage at end-user sites by satellite Internet. Full interactivity is not possible.
One-way terrestrial return satellite Internet systems use traditional dialup access to send outbound data through a modem and receive downloads from the satellite.
Two-way satellite Internet sends data from remote sites via satellite to a hub, which then sends the data to the Internet. The satellite dish at each location needs precise positioning to avoid interference with other satellites.
The key installation requirement is for the antenna to have a clear view toward the equator, where most orbiting satellites are stationed. Trees and heavy rains can affect reception of the signals.
Two-way satellite Internet uses IP multicasting technology, which allows one satellite to serve up to 5,000 communication channels simultaneously. IP multicast sends data from one point to many points at the same time by sending data in a compressed format. Compression reduces the size of the data and the bandwidth.


Wireless networking complies with a range of standards that routers and receivers use to communicate with each other. The most common standards are included in the IEEE 802.11 wireless local area network (WLAN) standard, which addresses the 5 GHz and 2.4 GHz public (unlicensed) spectrum bands.
The terms 802.11 and Wi-Fi appear interchangeably, but this is incorrect. Wi-Fi is an industry-driven interoperability certification based on a subset of 802.11. The Wi-Fi specification came about because market demand led the Wi-Fi Alliance to begin certifying products before amendments to the 802.11 standard were complete. The 802.11 standard has since caught up with and passed Wi-Fi.
From the point of view of teleworkers, the most popular access approaches to connectivity are those defined by the IEEE 802.11b and IEEE 802.11g protocols. Security was originally intentionally weak in these protocols because of the restrictive export requirements of multiple governments. The latest standard, 802.11n, is a proposed amendment that builds on the previous 802.11 standards by adding multiple-input multiple-output (MIMO).
The 802.16 (or WiMAX) standard allows transmissions up to 70 Mb/s, and has a range of up to 30 miles (50 km). It can operate in licensed or unlicensed bands of the spectrum from 2 to 6 GHz.

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