Retrive wifi signal from other devices?
I have developed some Android apps, but I am a newbie to hack something in Android. What I expect to know is if there is any way that I can get the signal information of wifi transmission from other device? For example, device A and device B are near to each other, and I want to write a program in device A to "know"(sniff) the packet of device B sending to its associated AP(even though that packets are discarded by device A because device A is not the destination). I have seen many app in Android using beacon from APs and analyzing their signal to noise ratio, but I can't find any app related to this idea(do the same thing to other devices rather than AP). Has anyone tried the same thing or any comment on this?