The invention provides a frequency hopping method for switching a hopping
carrier frequency in a predetermined hopping pattern based on a hopping
carrier table, in which there is provided intermittent receiving means
for starting carrier frequency designating means every constant cycle to
give a command for receiving the control channels of opposed radio base
stations. In the case in which a hopping order in a hopping carrier table
is skipped by n to carry out switching every intermittent receiving cycle
in an intermittent receiving operation, an intermittent receiving cycle
is set in such a manner that the n and a total number m of hopping
carrier frequencies in the hopping carrier table have a prime
relationship with each other.Moreover, the electric field strength of a
carrier frequency in a spare carrier list is measured by the intermittent
receiving operation and an interference counter of a spare carrier is
increased or decreased corresponding to a frequency at which the electric
field strength exceeds a predetermined threshold, and a carrier frequency
deleted from a hopping pattern is set to have the worst value as the
initialized value of the interference counter. A standby is maintained in
a state of a non-exchange until the frequency at which an electric field
strength measured for the frequency exceeds a threshold is sufficiently
reduced, and the same frequency is recycled as an exchangeable carrier
frequency after sufficiently confirming that a communication can be
carried out.