Arduino and Xbee for Rssi

I am starting a mini project where i want to set up a few stationary nodes in a small room (around 8m X 4m), and have couple mobile nodes, in which the stationary nodes pick up the RSSI from the mobiles nodes to estimate the distance between them.

I was wondering what products i would need? I have looked at some products and I and a noob in this and have no clue what the difference between the products are. The stationary nodes can be connected to a wall outlet for power and the mobile nodes need to have a battery so they can move around.

Any help is greatly appreciated.

Thanks

If you Google "Arduino RSSI", you will quickly learn that most (if not all) before you have failed calculating distance from RSSI.
Leo..

Small variations in the orientation of the antennas of the 'mobile' nodes will cause significant variations in signal strength which would translate into distance chnages when there have been node.

Other objects moving around in the room would have the same effect.

I have looked at some products

What have you looked at?
Expensive localization solutions at:
https://marvelmind.com/product/mini-rx/