A Historical Perspective on Predictive RF CAD Modeling and SimulationA predictive site survey, often referred to as a virtual site survey, uses predictive site survey software tools to develop a wireless network design. The computer-aided-design (CAD) predictive modeling software uses the building material construction to calculate RF propagation characteristics to provide a reliable predictive wireless network design plan for your site or facility. While a predictive site survey may be quicker than a physical site survey it's often a similar amount of time from project start to report delivery (and sometimes more costly) than a physical, on-site WiFi site survey. This is the result of the need to spend a non-trivial amount of time obtaining and assessing AutoCAD or other building floorplans to be sure that the predictive WiFi design software is properly configured. A predictive, virtual site survey WLAN design is only as good as the data that's provided by the wireless RF design engineer who's using the CAD software. Predictive designs are, however, very efficient for predicting channel assignments (to avoid channel overlap and co-channel interference problems), AP power settings (to develop an effective coverage cell map and support proper roaming) and to address project requirements where numerous buildings and floor are in-scope.
A predictive wireless survey allows a wireless survey of a building or area to be performed, and a wireless design with installation plans to be created, by using scaled plans of the area that requires WiFi coverage. Specialized WiFi virtual site survey, RF predictive CAD modeling and simulation software is used that allows building plans to be imported, obstructions (such as walls) to be added to the plans and 'virtual' APs to be added to the plan.
Connect802 provided virtual site survey, predictive RF CAD design services beginning in 2003. Predictive RF CAD modeling programs allow a WLAN design engineer to define in-scope coverage areas and test various AP placements in the virtual WiFi design which allows coverage down to the minimum usable RF signal level. Inasmuch as this type of design (where minimum bit-rate is provided at the edges of a coverage zone) is not suited for contemporary WiFi systems (which demand maximum bit-rate and capacity) the use of predictive RF CAD design has faded in the marketplace.
Ways In Which Predictive Wireless Design Software Was Applied Prior To 2020
There are several software tools that are well known in the world of predictive RF CAD modeling and simulation for wireless network design. Of the virtual site survey software tools, Wireless Valley LAN Planner and Wireless Valley Enterprise Planner, were the first well known predictive WLAN design software products, making their way into the market early in 2000. Wireless Valley became the market leader, competing against Ekahau and AirMagnet LANPlanner. Wireless Valley LAN Planner was purchased by Motorola, lost its momentum in the marketplace, and is now only a piece of 802.11 wireless design engineering history.
Using predictive wireless design software, a virtual, or predictive, survey would allow the designer to predict the propagation and coverage of an 802.11a/b/g or 802.11n WiFi wireless network. The predictive design software simulates propagation throughout a facility based on known building material characteristics. The predictive RF CAD modeling and design process starts with the import of a floor plan as an AutoCAD .dwg drawing file or an image file (JPEG, BMP), PDF, or DXF file. The drawing is then populated with material data identifying walls, interior obstructions (such as desks, furniture, file cabinets, etc.), elevator shafts, brick, cinderblock, or poured concrete walls, etc. The material data provides the known attenuation characteristics of that particular material of construction. After the drawing is fully defined, the virtual access points (APs) are placed on the drawing in the desired locations. The simulation is then run, and the expected propagation at the desired power level can be observed with a graph "heatmap" presentation.
Examples of Predictive RF CAD Modeling and Simulation Software for Virtual Site Surveys
From 2000 to 2010 the virtual site survey software market expanded to include predictive wifi design CAD modeling software with a number of products becoming available including (in alphabetical order):
AeroHive WiFi Planner Software
This planner was a free, web-based planning tool with Google Maps integration that will generate PDF reports showing AP locations, AP inventory, RF settings and heatmaps to help plan, configure and deploy an AeroHive WiFi network.