A base station for providing coverage enhancement, which expands, according to a coverage enhancement level, communication area in which communication between the base station and a terminal can be established, where the bigger level corresponds to the bigger expansion, the base station comprising: a control section that is adapted to configure a first or second number of demodulation reference signals, DMRSs, per subframe, according to the coverage enhancement level set in the base station for the terminal ; a receiving section that is adapted to receive an uplink signal including a subframe repeated a plurality of times, the subframe including a data symbol and the DMRSs, from the terminal ; and a channel estimation section that is adapted to perform channel estimation using the DMRSs included in the received uplink signal, the first number of DMRSs is configured when the coverage enhancement level is a first or a second, larger than the first, coverage enhancement level, and the second number of DMRSs, which is larger than the first number of DMRSs, is configured when the coverage enhancement level is a third, larger than the second, coverage enhancement level, the number of times for which the subframe is repeated in the received uplink signal increases from the first to the second and then to third coverage enhancement level, the second number of DMRSs is obtained by adding additional DMRSs to the first number of DMRSs, characterised in that the additional DMRSs are mapped to the first, fifth, eighth or twelfth SC-FDMA symbol, and the additional DMRSs mapped to the Single Carrier-Frequency Division Multiple Access, SC-FDMA, symbol are mapped to a resource element to which a rank indicator, RI, is mapped, whereby the RI is not used in coverage enhancement mode. a control section that is adapted to configure a first or second number of demodulation reference signals, DMRSs, per subframe, according to the coverage enhancement level set in the base station for the terminal ; a receiving section that is adapted to receive an uplink signal including a subframe repeated a plurality of times, the subframe including a data symbol and the DMRSs, from the terminal ; and a channel estimation section that is adapted to perform channel estimation using the DMRSs included in the received uplink signal, the first number of DMRSs is configured when the coverage enhancement level is a first or a second, larger than the first, coverage enhancement level, and the second number of DMRSs, which is larger than the first number of DMRSs, is configured when the coverage enhancement level is a third, larger than the second, coverage enhancement level, the number of times for which the subframe is repeated in the received uplink signal increases from the first to the second and then to third coverage enhancement level, the second number of DMRSs is obtained by adding additional DMRSs to the first number of DMRSs, characterised in that the additional DMRSs are mapped to the first, fifth, eighth or twelfth SC-FDMA symbol, and the additional DMRSs mapped to the Single Carrier-Frequency Division Multiple Access, SC-FDMA, symbol are mapped to a resource element to which a rank indicator, RI, is mapped, whereby the RI is not used in coverage enhancement mode. <EOS>