Pls help:802.11 wireless network signal strength simulators?

Hi all,

For my PhD I am working on algorithms for 802.11 networks (on the non-hardware/physical layer side). Therefore I would like to get a better feeling how the signal strength of an 802.11 network without base stations in ad-hoc mode is changing in an URBAN environment with mobile nodes. Therefore I am looking for a simulator where I can import the 3D Autocad model of my university, place a few nodes and look how the signal strength is changing if I move the nodes around. Ideally it would be not too complicated to use.

If somebody can recommend me a software for that purpose and maybe even provide a download location I would be more than happy!

Thanks very much,
Stoffdino

I have not seen any simulator that import from auto cad but if you can change it so you can open it with NAM(network animator), then you can simulate it with NS-2 simulator

Added after 7 minutes:

I upload NAM to test it