Machine-readable media, methods, apparatus and system for transmitting ACK/NACK signal in a wireless communication system are described. In some embodiments, a sequence corresponding to one of acknowledge (ACK) information and non-acknowledge (NACK) information may be determined. Then, the sequence may be mapped onto a transmission channel for later transmission from the mobile station to a base station. In some embodiments, the transmission channel may be allocated with at least a part of three feedback mini-tiles (FMTs), wherein each of the FMTs comprises two subcarriers contiguous in frequency domain by six orthogonal frequency division multiplexing (OFDM) symbols contiguous in time domain and the three FMTs being discontinuous in frequency domain.