WiFi Defined

The Basics

A common misconception is that Wi-Fi is short for “Wireless Fidelity”, but this is not the case. Wi-Fi is simply a trademark term meaning 802.11x owned by an organization, the Wi-Fi Alliance.

Wireless networks operate using radio frequency (RF) technology, a frequency within the electromagnetic spectrum associated with radio wave propagation. When an RF current is supplied to an antenna, an electromagnetic field is created that then is able to propagate through space. The cornerstone of a wireless network is a device known as an access point (AP). The primary job of an access point is to broadcast a wireless signal that computers can detect and "tune" into. Since wireless networks are usually connected to wired ones, an access point also often serves as a link to the resources available on the a wired network, such as an Internet connection.

In order to connect to an access point and join a wireless network, computers must be equipped with wireless network adapters. These are often built right into the computer, but if not, just about any computer or notebook can be made wireless-capable through the use of an add-on adapter plugged into an empty expansion slot, USB port, or in the case of notebooks, a PC Card slot.

Wireless Speed & Range

When you buy a piece of wireless network hardware, it will often quote performance figures (i.e., how fast it can transmit data) based on the type of wireless networking standard it uses, plus any added technological enhancements. In truth, these performance figures are almost always wildly optimistic.

While the official speeds of 802.11b, 802.11g, and 802.11n networks are 11, 54, and 270 megabits per second (Mbps) respectively, these figures represent a scenario that’s simply not attainable in the real world. As a general rule, you should assume that in a best-case scenario you’ll get roughly one-third of the advertised performance.

It's also worth noting that a wireless network is by definition a shared network, so the more computers you have connected to a wireless access point the less data each will be able to send and receive. Just as a wireless network's speed can vary greatly, so too can the range. For example, 802.11b and g officially work over a distance of up to 328 feet indoors or 1,312 feet outdoors, but the key term there is "up to". Chances are you won't see anywhere close to those numbers.

As you might expect, the closer you are to an access point, the stronger the signal and the faster the connection speed. The range and speed you get out of wireless network will also depend on the kind of environment in which it operates. And that brings us to the subject of interference.

Wireless Interference

Interference is an issue with any form of radio communication, and a wireless network is no exception. The potential for interference is especially great indoors, where different types of building materials (concrete, wood, drywall, metal, glass and so on) can absorb or reflect radio waves, affecting the strength and consistency of a wireless network's signal. Similarly, devices like microwave ovens and some cordless phones can cause interference because they operate in the same 2.4 frequency range as 802.11b/g/n networks. You can't avoid interference entirely, but in most cases it's not significant enough to affect the usability of the network. When it does, you can usually minimize the interference by relocating wireless networking hardware or using specialized antennas.

Data Security on Wireless Networks

In the same way that all you need to pick up a local radio station is a radio, all anyone needs to detect a wireless network within nearby range is a wireless-equipped computer. There's no way to selectively hide the presence of your network from strangers, but you can prevent unauthorized people from connecting to it, and you can protect the data traveling across the network from prying eyes. By turning on a wireless network's encryption feature, you can scramble the data and control access to the network.

Wireless network hardware supports several standard encryption schemes, but the most common are Wired Equivalent Privacy (WEP), Wi-Fi Protected Access (WPA), and Wi-Fi Protected Access 2 (WPA2). WEP is the oldest and least secure method and should be avoided. WPA and WPA2 are good choices, but provide better protection when you use longer and more complex passwords (all devices on a wireless network must use the same kind of encryption and be configured with the same password).

Unless you intend to provide public access to your wireless network — and put your business data or your own personal data at risk — you should consider encryption mandatory.


WiFi Historical Background

In 1985, Guglielmo Marconi opened the way for modern wireless communications by transmitting the three-dot Morse Code for the letter “S” over a distance of 3 km using electromagnetic waves. From this beginning, wireless communication, was developed into a key element of the modern society.

v This has not been so developed over the years when wired communication flourished.

v Not until in 1971 that the University of Hawaii pioneered the way to wireless networking in their development of ALOHA NET. This network was originally designed to solve the university’s dilemma of being able to transmit data to and from their four different sites scattered across the Hawaiian Islands.

Wireless Fidelity

v Wireless Fidelity underwent its development in the mid 1990’s, being developed by research groups at the Institute of Electrical and Electronic Engineers.

v Throughout the course of history, wireless networks have evolved from the simple wireless LAN based ALOHANET into the more sophisticated Wireless Fidelity concept, developed by the Institute of Electrical and Electronic Engineers (IEEE).

Shipping was a major early client for wireless telegraphy and wireless was standard for shipping by the time the Titanic issued its radio distress calls in 1912. Early on, it was quickly recognized that international coordination was required for wireless communication to be effective. This coordination involved two features.

v The potential for interference in radio transmissions meant that at least local coordination was needed to avoid the transmission of conflicting signals.

v With spectrum to be used for international communications and areas such as maritime safety and navigation, coordination was necessary between countries to guarantee consistency in approach to these services.

This drove government intervention to ensure the coordinated allocation of radio spectrum.

Since studying wireless communication is too broad, the researcher limits its scope into wireless networking more specifically the presently widely used “Wi-Fi”.

Wi-Fi was launched by Wi-Fi Alliance in 1985 it was the time when it was not utilized as commercially but have been just set to certain organizations for testing functions. Yet merely five years ago wireless networking was a niche. How did Wi-Fi get started, and become so successful, in depths of a downturn? Wi-Fi seems remarkable when you look at its provenance: it was, in effect, spawned by an American government agency from an area of radio spectrum

widely referred to as “the garbage bands”. Technology entrepreneurs generally

prefer governments to stay out of their way: funding basic research, perhaps, and

then buying finished products when they emerge on the market. But in the case of

Wi-Fi, the government seems actively to have guided innovation.