a radio communication system which includes a base station apparatus and
terminal apparatuses and performs TDD two-way communications using an
OFDM signal including subcarriers in a downstream communication from the
base station apparatus to each terminal apparatus, and an FH signal
having the same frequency band as that of the subcarriers in an upstream
communication from the each terminal apparatus to the base station
apparatus, the each terminal apparatus estimates transmission channel
characteristics of the subcarriers based on the OFDM signal received,
transmits an estimation result of the estimation unit to the base station
apparatus, and the base station apparatus assigns, to the each terminal
apparatus, at least one of subcarriers to be used in the downstream
communication of the subcarriers and a hopping pattern to be used in the
upstream communication, based on the estimation result transmitted from
the each terminal apparatus.