Cisco CISCO1005-CH Deployment Guide - Page 27
Professional Site Survey, RF Prediction with Optional Site Survey
UPC - 746320013343
View all Cisco CISCO1005-CH manuals
Add to My Manuals
Save this manual to your list of manuals |
Page 27 highlights
Deployment Determining Deployment Strategy Professional Site Survey Generally, the professional site survey involves temporarily placing one or more Cisco 1000 series lightweight access points and then measuring the resulting coverage(s). Based on the results of these measurements, Cisco 1000 series lightweight access points are relocated and/or reoriented to achieve complete coverage of the target space without unnecessary coverage overlap or coverage holes between Cisco 1000 series lightweight access points. This approach is appropriate given the following deployment requirements: • Full Coverage with 0% coverage holes • The RF characteristics of the building vary throughout the coverage area • The building type is not typical (Arena, Convention Center, Stock Exchange) During the Professional Site Survey, one or two access points are placed at or near one end of a building. Their coverage is measured and the access points are relocated and reoriented as necessary to ensure that this end of the building is completely covered. When measurements confirm that this is true, a second or third access point is added so its coverage area somewhat overlaps the coverage area of the first access point(s). (Generally, 10 to 15 percent coverage overlap is considered appropriate.) Its coverage is measured to ensure that its overlap with the first access point(s) is appropriate and to determine the coverage in the rest of the building. This process continues, adding a third or fourth access point and so on. This process continues until all areas of the building are covered. The professional site survey allows the designer to provide full seamless coverage; however, the Radio Resource Management (RRM) ensures that the channel assignments and transmit power levels are optimized for the Cisco WLAN Solution coverage area, freeing the site survey professional from having to fine-tune these variables. Other variables designers may include static transmit power level, geometric pattern used for access point placement, and the antenna type (omnidirectional, wide beam directional, or narrow-beam directional). Some designers like to have the flexibility to select antenna types most suited to specific buildings. Designers may differ in the criteria they use to determine coverage area. Some prefer to use signal strength (RSSI), some prefer signal-to-noise ratio (SNR), and others prefer to use some indication of throughput, such as packet retry rate. These measurements are normally made using site survey software provided by a wireless LAN manufacturer, running on a PC or PDA. They may also be made using one of the handheld measurement tools currently available, such as Air Magnet or Berkeley Varitronics. The measurement tools are usually selected based on their ability to measure the desired variable, RSSI, SNR, or packet retry rates. RF Prediction with Optional Site Survey RF prediction consists of importing the floor plans of the coverage area into a Computer Aided Design system in which a user can place access points, draw in the walls of the building and assign RF characteristics to the walls. Depending on the confidence level of the estimates made for the building RF characteristics and the cost of filling in potential coverage holes after deployment, an optional site survey may be appropriate to verify assumptions. This approach is appropriate given the following deployment requirements: • Full Coverage with 2 to 10% coverage holes • The RF characteristics of the building vary throughout the coverage area • The building type is not typical (Arena, Convention Center, Stock Exchange) 78-17279-01 Deployment Guide: Cisco Aironet 1000 Series Lightweight Access Points 9