FHSS - (Frequency Hopping Spread Spectrum)

FHSS (Frequency Hopping Spread Spectrum) : 

 — A 2.4GHz radio system which switches from one "free" frequency to another every few milliseconds. While jumping from one to the other frequency, you are not spending much time on that frequency and this keeps out interference. See also: DSSS.

Wikipedia:
Frequency-hopping spread spectrum (FHSS) is a method of transmitting radio signals by rapidly switching a carrier among many frequency channels, using a pseudorandom sequence known to both transmitter and receiver. It is utilized as a multiple access method in the frequency-hopping code division multiple access (FH-CDMA) scheme.