Wireless Internet Fundamentals

Many people associate using wireless Internet with WAP. Wireless Application Protocol, uses WML (Wireless Markup Language). WAP is generally used with portable devices such as cell phones and other hand held devices. WAP was designed for speed, flexibility, size, and ease of navigation. What we are going to talk about in this article, is accessing the Internet via normal desktop computers, via a TCP/IP wireless network. WAP is good for those of you that need Internet access when you are on the run, however it's not good for us that wish to have wireless access at home.

The wireless concept has been around since the mid 1800's. The first example of wireless can be seen as far back as the very first experiments with radio. Since then we have seen cordless telephones, remote controlled toys, long distance calling via microwave, and now, wireless Internet.

The problem with wireless Internet is there have been many inexpensive means of broadband access prior to its implementation. The many faces of DSL and cable are just two examples. As of now, money and time are two very expensive factors when taking wireless Internet into consideration. As a new technology, upfront equipment costs and contracts can be very nerve racking to the average Internet provider. Then one has to take into consideration the various engineering issues associated with wireless Internet technology.

In today's wireless Internet market, there are many key players developing fairly reliable, yet expensive hardware. As it is today, the market is growing rapidly, and technology in that area is growing right along side with it.

The Electromagnetic Spectrum

The Electromagnetic Spectrum, is the full range of frequencies, from radio waves to gamma-rays, that characterizes light.

As with other radio signals, wireless operates in the radio band on the Electromagnetic Spectrum, below the Infrared and visible bands of light. Starting from bottom to top on the Electromagnetic Spectrum we have:

• Radio
• Infrared
• Visible
• Ultraviolet
• X-ray
• Gamma-ray
• Cosmic-ray

The higher you get on the list, the closer together the crests on the waves get ( this is measured in wavelength ).

Electromagnetic radio radiation has the lowest frequency, the longest wavelength. Radio waves vary with wavelengths to about twenty meters apart.

The FCC ( Federal Communications Commission ) maintains and allocates every frequency in the radio band which is between 9 kilohertz and 300 gigahertz. For more about the radio spectrum and frequency allocation, visit the FCC Radio spectrum home page here.

As of now, a typical Line of site Internet connection operates at a frequency of 2.4GHZ, which is an unlicensed frequency. With current technology, this allows for decent bandwidth up to 10 miles in distance or more depending on engineering factors. With non-line of site, the frequency being used is 900MHZ. The same for cordless phones, and many other devices. However, currently distance is very limited at less than 3 miles.

The Fresnel Zone

The Fresnel Zone ( the s is silent, pronounced 'fre-nel' ) is the area between two line of site antennas where the radio waves spread out after they leave. The more obstructions in this area, the more the signal will weaken. As stated earlier, line of site is typically 2.4GHZ. Which is microwave. Microwaves can pass through walls fairly easy, but trees and other vegetation is much more of a problem. This is primarily due to the higher water content in vegetation.

Take a flashlight for example. The light radiates from its source, and the light dissipates and widens as it gets further from the flashlight itself. The highest concentration of light is in the center of the flashlight. Now take two flashlights, turn them on in the dark, and line them up so they are even, facing each other, about 10 feet apart. Now stand off to the side. Notice how the center is brighter than the rest of the area? Consider that the Fresnel zone.

Take this picture above. The two lines on the right and left represent two wireless radio towers, the pea green color represents the terrain, and the red represents the Fresnel zone. This red area is the most important area to keep clear of obstructions. The more obstacles in the way, the weaker the signal will become.

Summary

I hope this gives everyone a bit more insight on how wireless Internet works, and the technology and engineering that needs to be perfect to make it all work just right.

Bottom line is, despite several broadband Internet access types around currently, wireless will be a major player in the years to come. Especially for those that do not qualify for DSL, or wish to have something more reliable than frame relay or ISDN.

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