How do wireless devices eliminate noise?

[Brainguy]

Let's say I have a wireless device, one that works on radio frequencies, let's say it's a remote control car that operates on 100ghz for example's sake. If I were to try operating this car with its intended remote, but then have a friend broadcast similar frequencies, I would obviously get some interference. But with many things like this, They can be programmed to only respond to a certain source, in essence, the car would be able to tell commands from its intended remote part from those coming from the unauthorized one. If someone is able to point me in the right direction in finding out how this happens I would greatly appreciate it.

 

[rcgldr]

In the case of older radio control model transmitters and receivers (50mhz, 72mhz), a separate band of frequency had to be used for each model that was being operated within the same area (about a 3 mile radius). In the case of current radio control transmitters and receivers (2.4ghz), there are two types of "spread spectrum" methods used to avoid interference, wiki articles:

http://en.wikipedia.org/wiki/DSSS

http://en.wikipedia.org/wiki/FHSS