An apparatus (UEA) may generate a zero-tail signal to be transmitted in an LTE/LTE-A cell, by introducing time domain samples with zero power or very low power in specific positions of a time symbol tail. The apparatus (UEA) may transmit the generated zero-tail signal to a base station (eNB), such that a first user terminal (UEA) is located in the cell farther away (e.g. on a cell egde) from the base station (eNB) than a second user terminal (UEB). Thus coexistence of signals sent by user terminals (UEA, UEB) located at different distances from the base station (eNB) within a same receiver window is enabled without inter-symbol interference. The generated zero-tail signal may also be transmitted from the first user terminal (UEA) or from the base station (eNB) in an outdoor system that is detectable by a neighbouring indoor system.