User Manual

Appendix
BreezeNET PRO.11 Series 8-20 User’s Guide
D: distance between sites
Figure 9.13: Fresnel Zone Clear of Obstacles
When at least 80% of the first Fresnel Zone is clear of obstacles,
propagation loss is equivalent to that of free space.
8.5. IEEE 802.11 Technical Tutorial
The purpose of this chapter is to give technical readers a basic overview of
the new IEEE 802.11 Standard, enabling them to understand the basic
concepts, principles of operation, and the reasons behind some of the
features and/or components of the Standard.
The document does not cover the entire Standard and does not provide
enough information for the reader to implement an 802.11-compliant device
(for this purpose the reader should refer to the Standard itself).
8.5.1. Architecture Components
An 802.11 LAN is based on a cellular architecture where the system is
subdivided into cells. Each cell (called Basic Service Set, or BSS, in the
802.11 nomenclature) is controlled by a Base Station (called Access Point
or, in short, AP).
Although a wireless LAN may be formed by a single cell, with a single
Access Point, (and as will be described later, it can also work without an
Access Point), most installations will be formed by several cells, where the