A method and device in a UE and a base station used for wireless communications. The UE first receives a first signaling, and then transmits a first radio signal; the first signaling is used for determining K REs, and K first-type complex numbers are used for generating a baseband signal of the first radio signal through a baseband signal generation for generating an SC-FDMA baseband signal, a modulation scheme employed by the first radio signal is π/2-BPSK, K first-type parameters respectively correspond to the K first-type complex numbers, the K REs occupy contiguous subcarriers in frequency domain. The K first-type parameters are related to a center frequency of the contiguous subcarriers occupied by the K REs, each of the K first-type parameters is related to a length of cyclic prefix of an RE onto which a corresponding first-type complex number is mapped. The present disclosure improves uplink coverage performance.