1. A base station that performs radio communication with a radio terminal using at least one narrow frequency band where the number of resource blocks is limited to a predetermined resource block number, the base station comprising:a transmitter configured to transmit, to the radio terminal, configuration information for frequency hopping where the radio communication is performed while switching the narrow frequency band; and
a controller configured to allocate, to the radio terminal, a first frequency band of the frequency hopping and a frequency band of a hopping destination, wherein
the first frequency band and the frequency band of the hopping destination respectively include the narrow frequency band,
the first frequency band further includes the fraction resource blocks,
the fraction resource blocks are resource blocks, the number of which is smaller than the predetermined resource block number and are positioned adjacently to the narrow frequency band in a frequency domain, and
the transmitter is configured to receive, to the radio terminal, a notification indicating whether or not the fraction resource blocks are to be used in the radio communication with respect to the frequency band of the hopping destination when the first frequency band includes the allocated fraction resource blocks and the frequency band of the hopping destination does not include the allocated fraction resource blocks.