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Range Parameter
May 20,2007 00:00
by
admin
Range Parameter The range parameter defines the distance to which typical products based on the technology can propagate data. For a wireless LAN, the range is generally the distance between an access point and a radio card installed in a client device, such as a laptop. As an example, the range of 2.4GHz wireless LANs is 150 to 900 feet, depending on the data rate, output power, and facility construction. If all other attributes are equal, an increase in data rate decreases the effective range (and vice versa). Range affects the requirement for geographical coverage area. A longer range enables the construction of a wireless LAN having fewer access points and covering a wider area. Table 8.1 identifies the affect that specific types of material have on the transmission of RF signals. TABLE 8.1 Attenuation Effects of Various Elements Relative Degree of RF Barrier Attenuation Example Air Minimal Wood Low Office partitions Plaster Low Inner walls Synthetic material Low Office partitions Asbestos Low Ceilings Glass Low Windows Water Medium Damp wood, aquariums Brick Medium Inner and outer walls Marble Medium Inner walls Paper High Paper rolls, cardboard boxes Concrete High Floors and outer walls Bulletproof glass High Security booths Metal Very high Desks, office partitions, reinforced concrete, elevator shafts, warehouse shelving As an example, metal offers very high attenuation to the propagation of radio signals, which significantly limits the range of the wireless LAN. When defining this parameter or particular technologies, be sure to consider attenuation characteristics of the typical environment where the wireless LAN will operate. |