A wireless device generates a synchronization signal for maintaining synchronization and transmits the synchronization signal in a subframe containing a plurality of orthogonal frequency division multiplexing (OFDM) symbols. The first OFDM symbol in the subframe is divided into a first part and a second part, the last OFDM symbol in the subframe is divided into a first part and a second part, and the synchronization signal is transmitted in the second part of the first OFDM symbol and the first part of the last OFDM symbol.