Assuming I have an Access Point and I measure the signal strength and noise at some points around the Access Point. Is there a formula to draw a coverage map. Also are there any free tools available for drawing such a coverage map?
It really depends on what you're trying to graph as to what the formulae is. When graphing wireless information I tend to graph any one of the following:
- Signal strength
- Signal to Noise Ratio
- Packet Retries, etc.
There is an awesome piece of software that was just release recently by AirMagnet) called AirMagnet Surveyor. It will graph all sorts of information against a floor plan however it's about AUS$3000 so its definitely not free.
In its place I have manually taken readings and used Adobe Photoshop before today to produce pretty pictures for clients. It's time consuming and labor intensive however it will accomplish the same thing as AirMagent Surveyor without the capital expense.