A user terminal, comprising: a reception section that receives a downlink signal transmitted from a radio base station in a single carrier transmission system; a channel estimation section that performs channel estimation using a reference signal included in the downlink signal; and a demodulation and decoding section that demodulates and decodes a downlink control signal and a downlink data signal included in the downlink signal using a result of the channel estimation, wherein a plurality of downlink control signals for a respective plurality of user terminals including the user terminal, a plurality of downlink data signals for the respective plurality of user terminals, a first reference signal referred to when the plurality of the downlink control signals are demodulated, and a second reference signal referred to when the plurality of the downlink data signals are demodulated are mapped in a time domain in the downlink signal, wherein at least one of the first reference signal and the second reference signal is common to the plurality of user terminals, and wherein the demodulation and decoding section demodulates and decodes the downlink control signal addressed to the user terminal using a channel estimation result based on the first reference signal, and demodulates and decodes the downlink data signal addressed to the user terminal using a channel estimation result based on the second reference signal and using the downlink control signal addressed to the user terminal; wherein the first reference signal that is specific to each of the plurality of user terminals, and the second reference signal that is common to the plurality of user terminals are mapped in the downlink signal, and wherein the demodulation and decoding section demodulates and decodes the downlink control signal addressed to the user terminal using the channel estimation result based on the first reference signal addressed to the user terminal, and demodulates and decodes the downlink data signal addressed to the user terminal using the channel estimation result based on the common second reference signal but based not on a reference signal specific to the user terminal and using the downlink control signal addressed to the user terminal. a reception section that receives a downlink signal transmitted from a radio base station in a single carrier transmission system; a channel estimation section that performs channel estimation using a reference signal included in the downlink signal; and a demodulation and decoding section that demodulates and decodes a downlink control signal and a downlink data signal included in the downlink signal using a result of the channel estimation, wherein a plurality of downlink control signals for a respective plurality of user terminals including the user terminal, a plurality of downlink data signals for the respective plurality of user terminals, a first reference signal referred to when the plurality of the downlink control signals are demodulated, and a second reference signal referred to when the plurality of the downlink data signals are demodulated are mapped in a time domain in the downlink signal, wherein at least one of the first reference signal and the second reference signal is common to the plurality of user terminals, and wherein the demodulation and decoding section demodulates and decodes the downlink control signal addressed to the user terminal using a channel estimation result based on the first reference signal, and demodulates and decodes the downlink data signal addressed to the user terminal using a channel estimation result based on the second reference signal and using the downlink control signal addressed to the user terminal; wherein the first reference signal that is specific to each of the plurality of user terminals, and the second reference signal that is common to the plurality of user terminals are mapped in the downlink signal, and wherein the demodulation and decoding section demodulates and decodes the downlink control signal addressed to the user terminal using the channel estimation result based on the first reference signal addressed to the user terminal, and demodulates and decodes the downlink data signal addressed to the user terminal using the channel estimation result based on the common second reference signal but based not on a reference signal specific to the user terminal and using the downlink control signal addressed to the user terminal.