Shameless plug: I made a wireless network emulator [0] for my dissertation. It's a userspace implementation with a lot of extra user/kernel context switches for every packet, so too slow for emulating latencies and only deals with packet loss. But it takes wireless congestions into consideration, and can emulate CSMA/CA. For one node this wouldn't make a difference, but for multiple nodes where interference is a problem, it's a bit more realistic than just setting arbitrary packet loss.

[0] https://github.com/squirrel-land/squirrel

EDIT: typos