Hop Set
The IEEE 802.11 Standard specifies three hop sets, which are pre-defined sets
of frequencies that IEEE 802.11 Frequency Hopping systems MUST use. These sets
have been chosen to minimize interference between nearby systems, and have been
required by the various regulatory bodies in specific countries, such as the
FCC in the United States, ETSI in Europe, and MKK in Japan. Refer to the IEEE
802.11 Standard for more information on hop sets.