ve to pass through walls, ceilings, floors or other obstructions. Path loss is also highly frequency dependent and for all practical purposes a line-of-sight is required for communication in the 5 GHz band. Table 7-6: WLAN Indicative Indoor Range vs. PHY Data Rate PHY data rate (Mbps) 802.11a 802.11b 802.11g Implementing Wireless LANs Selecting the Technical Solution With the demise of competing standards such as HiperLAN/2 and HomeRF, the essence of the technical choice is simply - which 802.11 flavour best fits the bill? While the requirements analysis may point to a clear winner among the available technical options, if a selection needs to be made between operating in the 2.4 or 5 GHz bands then an RF site survey, described in the next section, should be conducted as an input to that decision. Similarly, if the requirements dictate that network capacity needs to be stretched beyond the throughput of a single channel, for example with multiple access points fully exploiting non-overlapping channels, then an initial physical layout may need to be made for both 2.4 and 5 GHz options. Some on-site physical testing may also be valuable prior to making the final decision, for example to confirm the achievable range if a 5 GHz network is envisaged in a constricted indoor environment. Future hardware developments may soon make the choice between 2.4 and 5 GHz operation irrelevant. As increasing volumes of dual band radios are shipped, supporting both 802.11g/b and 802.11a, and prices fall to parity with single band products, it will be cost-effective to implement a dual band WLAN that makes the best use of the characteristics of both RF bands. Planning and Designing the Wireless LAN Surveying the RF environment Conducting a site survey is an important step in planning and designing all but the simplest WLAN. It is important to determine the impact of environmental factors on radio wave propagation in the operating area of the LAN, and also to test for the presence of RF signals that will interfere with WLAN performan