Building a Cisco Wireless LAN
A comprehensive, step-by-step guide to employing Cisco Wireless LAN Architecture.
TABLE OF CONTENTS Building a Cisco Wireless LAN
Wireless Design Considerations
In order to create a design for a wireless system, you must consider common wireless LAN transmission and reception impairments, such as attenuation, radio frequency (RF) interference, and application and structural considerations. As you will see, many of the design considerations in this section relate to point-to-point and point-to-multipoint wireless implementations, which is mainly because wireless coverage in these implementations is not spread out over an area, but rather it is focused to a specific point. This section explains various common types of impairments and considerations that you may face in your wireless design and testing efforts.
Attenuation
Attenuation is the decrease in strength of a radio wave; the strength decreases as the distance from the antenna increases. It can be caused by the natural conductivity or resistance of all sorts of physical matter, but the greatest resistor to radio waves is the Earth. Radiated energy from the Earth, and interference from trees and buildings will cause attenuation of the signal's ground waves, as radiated energy and interference from water and dust particles in the atmosphere will affect the signal's sky waves. You must plan your design and equipment use based on these factors affecting ground and sky wave propagation, such as transmitter height, distance between transmitters, and solar radiation factors. Low-frequency radio wave propagation utilizes propagation of both ground and sky wave transmissions and can be used at varying distances; high-frequency wave propagation (3,000 kHz to 30 Mhz) relay more upon sky waves for transmission and...
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